It's pinging under load and distributor is a recurved Duraspark.

The dual point CJ engine is the only one listed with a 16 degree spec. Even the Boss351 specs at 6 degrees.

do you know what cam is in it and what the intake valve center line is degreed to?

more importantly to your timing question, do you know at what point in degrees ABDC the intake valve actually closes? this number is critical in determining your Dynamic Compression Ratio, the static compression ratio and the closing point of the intake valve set the point that the cylinder begins to compress the contents, a mild or economy cam will close the intake valve early and create higher cylinder pressure (more prone to pinging) and a more serious performance cam will close the intake valve later creating less cylinder pressure which is compensated for with more static CR. too much static CR and an intake valve closing too early makes for an engine that will not tolerate normal ignition spark advance. your cranking cylinder psi can be a good indicator of a situation like that

to the actual timing number themselves, 16* BTDC is not unusual at all, 18* is better. you also want to find your 'total timing' which does not include any vacuum input, only mechanical. with a timing light set up and a scale on the damper able to read at least 40* BTDC, gently rev the engine until you see the timing advance stop advancing, what does the pointer on the damper say? typical is 36*-38*

another important factor is how quickly the timing advances, controlled by the tension of the mechanical advance springs. light springs can allow the advance to dial in too quickly causing ping

I do have quite a bit of that info if you're so inclined to opine. 😆

The cylinder PSI is between 174 and 179.

The compression is about 10.3:1

Cylinder heads are early 70 screw in studs

Recurved Duraspark and factory blue grommet box

Edelbrock F351 intake and 750 CFM carb

Factory exhaust manifolds.....I know.

Roller cam (Howard's) and rockers

Cam card.......

The distributor has a 20 degree advance.

I also had to drop the idle because of run on but it runs decent.

I started at 6 degrees because every other version of the Cleveland including the Boss 351 used that setting. I don't know why the dual point used 16 degrees but my car didn't like it.

I'm going to try 8 and 10 degrees and see how it runs but I'm going to stay on the soft side until I can get it on a Dyno. I have a feeling the carb might need jetted and or some secondary tweaking.

it's not a timing issue, it's not a vacuum advance issue, it's not a distributor curve issue, it's a cylinder pressure issue.
the intake valve closes too early for the static compression ratio in the motor

OK from the cam card i figure the intake valve closes at 60.3* ABDC

this is very early for a 10.3:1 motor, here's the results from the Wallace DCR calculator

Static compression ratio of 10.3:1
Effective stroke is 2.82 inches
Your dynamic compression ratio is 8.49:1
Your dynamic cranking pressure is 176.73 PSI
V/P (Volume to Pressure Index) is 153

8.49, let's call it 8.5" DCR, 1/2 a full number too high for any pump fuel. 1/2 a full number over maximum, not from some safe point midway between soft and maximum. the engine would run well with a full number less DCR, 7.5:1. 7.7-7.8 is a good margin of safety for keeping away from the ping zone, 3/4 of a full DCR number would set it in the middle of safe for pump premium. but the Wallace nailed the cranking psi pretty much dead on!

messing with the Wallace what i find is the cam is closing the intake at least 10* too early for the rest of the motor. a 70* ABDC ICV (Intake Valve Close) makes just under 7.9:1 DCR, high side of safe 91 octane might not quite cut it? an IVC of 72* ABDC makes 7.75:1 DCR dead on that middle of safe point i mentioned above. me personally i'd change the cam out for a candidate that closes the intake valve no earlier than 72* ABDC 'on the seat'. 'on the seat' means ADV numbers not .050". to convert .050" to ADV do what i did, add 1/2 the difference to the .050" number, in this case the numbers are 269 (ADV intake degrees of duration) and 217 (intake degrees of duration at .050"). divide the difference 52 by /2 to get 26 and add that to the 34.3 at .050" IVC shown on the back side of the cam card. this cam closes the intake valve 'on the seat' at 60.3* ABDC. so just to be clear a cam that closes the intake at 72* ABDC or later (73*, 74*, 75*) will correct your ping problem. IVC at 75* ABDC makes 7.54 DCR, that's about as late as i would go to preserve the most thermal efficiency possible. look at the DCR's listed in George's chart as a comparison. also notice the differences between the advertised (published) compression ratios vs George's calculated numbers

I was thinking the DCR seemed high and that the cam seems short for the compression ratio, but I am no expert on engine builds.  I figured Rock would set things straight. 

What heads are you running Chuck?  Are they the early 4V close chambered?  If they are, do you still have the original open chamber heads?  Rock, what about a head swap to lower the compression versus a cam swap?

That's the bad news I was considering when I did the compression test last month. Couldn't hear the ping until I had the exhaust put on last week. 

If I understand what you put down I need a cam with 230* @ .050 for the intake? (As I'm thinking about that the point where the intake closes seems to be of more importance) 

My problem being the .611 lift on these cams is slightly higher than recommend without lifter bore sleeves. I maybe as wrong about my max lift concerns as well after rereading this (I'm using the Lunati's)  https://www.tapatalk.com/groups/clevelands/351c-hydraulic-roller-lifters-and-steel-distributo-t16728.html" rel="nofollow - 351C Hydraulic Roller Lifters and Steel Distributor Gears - Cleveland's Forever (tapatalk.com)    

I do have a small airport near by with 100 octane low lead. I was running that exclusively for the first 250 miles. Do you think that might be high enough in the short term? Season is almost over so I'd probably look at swapping a cam this spring.

Edit: What do you think of retarding the timing on this camshaft to lower the DCR? The original 72 camshaft was ground 4* retarded? Would that not be enough in this case?   

Yes and No.

I hate the thought of doing another cam but it's the path of least resistance assuming I don't have to pull the engine for rod bearings. Might wing that with only 400 miles ?

On the other hand I was going to have to pull the intake to go with an air gap anyway.

that's an option but likely more $ than just swapping the cam. 76cc chambers makes 8.8:1 static and 7.3 DCR. mill the open chamber heads to 70cc chambers and you're right back at 7.75 DCR with a static CR of 9.35:1, factor in possible custom pushrod length and intake manifold milling to match the ports and bolt holes

if the open chamber heads are in serviceable condition as-is then it's a direct fit only $ is gaskets. for that matter all the valves and hardware can be transferred over all they could need is guides, valve job on the seats and cut the spring seats if needed, machine for screw-in studs? that's still a lot of work ($)

i did try plugging 4* retard into the Wallace and it didn't do nearly enough to calm it down, the problem with doing that if it's an option is that the 4* retard across the board affects all 4 valve timing event rather than only the IVC that you want to change. it would kill the cam the same way Ford did it in 1972 then again in 1973 for a grand total of 8* retard for the Cobra-Jet 

having run it on LL100 for most of the time so far reduces the amount of damage to the rod bearings that may be done, that's going to be your call. my 1st build i lost the #7 rod bearing total overlap in a couple days after firing it up, 11:1 static with a decent amount of cam but i ran it on regular IIRC. i had no clue on DCR back then so no idea how high it was but it sounded like Orville Redenbacher was busy under the hood. crank kit was only $135 at that time!

me personally i'd swap the cam and assuming they pass inspection use the same lifters, you know they're good. i wouldn't risk starting over with a set of unknown likely chinesium lifters. i've been seeing many youtubes showing new lifters from the box with with no convex radius on the foot, dead flat guaranteed to kill the cam. then there's the internal clearances that have gone to , new production lifters can't even hold oil to pump themselves up, they just bottom the plunger with the slightest of pressure

OK i just caught that your cam is Hyd-Roller, i'd use the same lifters for sure, no wear pattern to worry about. between your cam card and the Summit specs i'm seeing .571"-.576"/.577" lift?

https://www.summitracing.com/parts/hrs-233215-10

lynchster wrote: If I understand what you put down I need a cam with 230* @ .050 for the intake? (As I'm thinking about that the point where the intake closes seems to be of more importance.

for whatever reason i don't relate to .050" numbers in many regards, the 50 numbers are 'all over the place' due to the ever increasing lobe ramp lift rates lately. sometimes this is referred to as 'lobe intensity'. for this same reason i like the Wallace DCR calculator because it uses Advertised or valve on the seat duration for it's input. the 50 number / intensity can vary wildly from cam to cam

so now the quest for a cam that suits all the existing parameters, mostly your valve spring package already installed forgive me i forget what transmission you're running there, manual or auto, any stall converter?

looking at the Howards page i find this cam

http://www.howardscams.com/hydraulic-roller-camshaft-1970-1983-ford-351c-351m-400-2800-6400-howards-cams-231175-10" rel="nofollow - https://www.howardscams.com/hydraulic-roller-camshaft-1970-1983-ford-351c-351m-400-2800-6400-howards-cams-231175-10

.594"/611" 233*/241* but darn Howard doesn't let you see the cam card. all things being equal (mostly the 0-.050" ramp rates) if you need an additional 12* more duration on the IVC then figure you need 24* total added on to the adv duration of the cam. this puts the cam into a different classification and will need a converter if auto trans. 24* is kind of a lot. your 217* at 50 intake cam + 24* makes 241* at 50.

Howards has a 243* at 50 intake cam,

http://www.howardscams.com/hydraulic-roller-big-daddy-rattler-camshaft-1970-1983-ford-351c-351m-400-2400-6200-howards-cams" rel="nofollow - https://www.howardscams.com/hydraulic-roller-big-daddy-rattler-camshaft-1970-1983-ford-351c-351m-400-2400-6200-howards-cams

but IDK if it fits the existing parameters or if you're up for that much cam?

how much work / what will your open chamber heads need?

how do you feel about leaving everything else the same and changing the pistons?

the 1973-74 8cc dish piston makes 9.65:1 static and 7.95 DCR

what's the bore in your block?

If the camshaft is the only real worrisome issue, I'd try to minimize the work and just change the cam. The cost and trouble for any changes to other parts hugely raises the costs. I'm expecting to need $1500+ just to refresh my 351C-4V by upgrading the cam to roller, going through the heads to verify quality, and being sure the oiling system can supply enough to bearings at 6500rpm.

I'd contact a trust worthy custom cam source for the Cleveland, and have them create the best cam for the parts combination. I don't like any OTS cam made for different combinations than your parts. The cost of custom is about $100 plus any special valves springs etc. It's not worth the trouble to guess at a cam, or use a cam someone else guessed at, or one some software guesses at. I want one that an expert designs for my actual combination, that is very well worth $100 to me.

I hope I can find a local shop that has worked on many great Cleveland engines, and one that can competently install lifter bore bushings. Feasible is another subject, who knows.

i suspect George Pence has exactly what the doctor ordered, most of his cams are spec'd to the Closed Chamber / Flat Top flavored 351C. every instance i've seen on the Pantera International page when a fella (myself included) calls Bullet to get a Pence grind done, they want to change the specs. why? a guy can't order the cam he wants w/o getting with? so many guys say "call the cam company and give them your info ... do that 3 times a day 5 days a week and you'll get 15 different cams, why? granted 1 of those cams ~might~ stand out above the rest but for sure 1 of them is going to bottom of the list, is that the cam you got? IDK

reason i through out changing the pistons is because i do happen to have a set of .030" TRW forged 1973-74 dished on rods with good bolts. i grabbed them from a guy advertised them on the Clevelands Forever FB page for no reason other than they don't make'em no mo. possible a good cheap blower piston if i ever use them, possible i won't, i'd let them go if a guy needed them. and i will say i was very impressed with them when they arrived, i've never seen connecting rods that clean, and very minimal wear / use / storage marks on the pistons. i have no qualms about using them myself. more work than swapping the radiator cap but everything else stays the same, could be the easiest and still a cost effective solution at the end of the day

Based on this conversation the car is offline again. 

I believe Howard's are the only one doing standard base circle cams. The valve springs match this cam and I'm not looking to swap them if I can avoid it. If these springs are the same for the more agressive cam I might consider that. The .611 lift on the exhaust doesn't seem that much more but I've been wrong before.

The other option is having them grind one with an acceptable IVC spec. Maybe opening up the centerline from 110 to 112 to help reduce cylinder pressure and take the lift as high as the springs allow.

I'm really looking for an option where I don't have to pull the engine if I can avoid it. Still a PITA pulling the rad, hood latch support, and grille though. Thinking about rolling the dice on the rod bearing since it doesn't have many miles on it but this project is months off so that decision can change. 

This is "knowing enough to be dangerous" in application. 🤷

I only mentioned the heads because I thought you were running closed chambered and though your might have a set of open chambered heads just sitting around, but obviously not the case.  I like Rock's idea of the piston swap, it would also give you a chance to inspect the rod bearings.  Plus it eliminates the worry of getting a poor quality new cam and the break-in.  But that means pulling the engine....

If you do go with a new cam, a custom grind is the way to go for sure.  Talk to George and hoepfully he will help you out.  What gears are you running in your car?  Just wondering how they will work if you go to a longer duration cam.

Those sound like a very nice set of pistons to reduce the compression some from closed chamber heads.

I'd be careful with that idea too, I would have the whole assembly rebalanced if I changed the pistons.

a couple misnomers i've caught that i feel should be addressed, overlap doesn't play a roll in reducing cylinder pressure, overlap is the opposite side of the 4 cycle chart from where the intake valve closes. overlap is the period between the closing of the exhaust valve and the opening of the intake, both valves are open at the same time. there is no cylinder pressure to speak of anywhere near the overlap period. the other you just mentioned is the lobe separation angle, that also does not play a roll in reducing cylinder pressure but it can affect overlap unless the lobe is tailored to counteract gaining or losing overlap. the only valve timing event that controls now much cylinder pressure is produced is the IVC (intake valve close) on the seat

another option to reduce static CR is to 'relieve' or 'soften' the combustion chambers. if you were to remove 8 cc's of material from the chambers you'd be at 9.4:1 static and 7.75 DCR. here's a pic of an Aus 2V closed chamber head that a guy softened to fine tune his static CR. unshrouding the intake valve also improves flow

i guess you could say it's posted on

http://www.tapatalk.com/groups/clevelands/cleveland-s-forever-network54-351c-f1/" rel="nofollow - https://www.tapatalk.com/groups/clevelands/cleveland-s-forever-network54-351c-f1/

and http://pantera.infopop.cc/forum/engines-and-engine-systems" rel="nofollow - https://pantera.infopop.cc/forum/engines-and-engine-systems

a bunch of were hoping George Pence would put all of it together, still no word on his health

1. Based on cylinder psi the calculator puts my compression closer to 10.4 -10.5

2. Three Howard Cams matched to 9.0, 9.5, and 10.1 wind up at just about 150 psi. 

3. According to George Pence the cast heads can manage 8.0:1 dynamic compression. Alloy heads 8.4:1.

I think his very informed opinions and his preference for sports car performance versus muscle cars lead to his preference for sub 8 dynamic compression ratios and higher lsa's.

I don't think he's wrong. The higher pressures don't lend themselves to the durability of factory produced and warrantied drivetrains. Piston rings would last longer and high stress abuse would crack these blocks 50 years ago.

4. I'm just guessing here and I could be wrong again. With the improvement of just pulling the timing to 6 degrees I could probably run colder plugs, better than 90 octane fuel, and jet the carb richer but for what? I'm still losing 10 degrees of timing, giving up a lot of power, and still stressing the engine.

5. I haven't found the specs for the cams Pence did but I suspect they're flat tappet designed. I wish I had a Dyno program so I could play with camshaft profiles. 

The one Howard's cam with a 69* IVC is close but I wouldn't mind tweaking the specs on it to drop a bit of lift and maybe shift the LSA a bit to get closer to 72* IVC. 

I called Howard's today and my springs are good for the .611 lift too but I don't know about piston clearance or the oil band height.

The guy also thought a 75* ICV was crazy. Obviously not a Cleveland guy. 😆

6. Not sure I want to do this swap myself just yet. Daily driver? Sure. Converted engine that cost more than most cars I drive not so sure.

7. Conflicting information:

Read psi for street cars between 150 and 200 psi. (WTF?)

Seen compression test on a Cleveland at 180 psi. Two cylinders were at 150 though.....

Feel free to throw out thoughts, criticisms....

     

The camshaft is the biggest key to cylinder pressure and all of the aspects of performance, all rpm's and driveability. The cam should be the last component chosen, designed, to mate the other hard parts together. So given the apparent issue, I think the rest of the parts are decent choices and usable as is.

I think unless a full tear down and refresh etc is in order, I'd re-select the cam and do the minimum to get it back running. If it had to some apart, I'd reinspect the whole oiling system and head parts(valve seats and guides etc), plus upgrade the pistons for lighter and adjust compression if needed. I like the 10.5:1 range for performance use, with premium, with a custom cam(not off the shelf). It's better to run a point less compression if you are going to guess at a cam. A custom cam can be made to work with 11:1 and more.

A proper cam designer(who knows how to make one for a Cleveland) should be able to create specs to work with the existing compression etc. But also a custom cam often needs to(or it's free power) upgrade the springs(lighter and thus quicker, more power yet and/or better lifespan). You have to be very specific with a designer to get all of the benefits of a custom cam. The 302 and 351W market is full of countless engines built with custom cams that function amazingly well, many with mismatched parts that the cam manages well.

The cam I'll have to work on now that it's cold

What do you mean in your third point?  Are you saying that George is conservative or too aggressive on the DCR because he does sports car engines?  I am not really sure what you mean.  My engine has mid 7s for DCR and I wouldn't want too much higher than that, especially since 91 Octane is the best I can get. 

I agree with Rock, your DCR is too high. The way I see it is you have two viable options. 

First, replace the cam, which probably will move your power band, which is why I asked what gears you are running. I suggested asking George for a cam grind, but I didn't know his health was down.  It's too bad because he did help me out when I was doing my build.  In the end I used a custom grind designed by Tim Meyer.

Second, reduce the compression, either with new pistons, or by increasing the combustion chamber size like Rock showed above.  If you are pulling the intake, pulling the heads to work on the chambers might be not too bad of a job, but I can't say I'd want to go at the combustion chambers with a die grinder, I'd worry I'd mess something up.  Maybe you are up for that kind of work or there is some in your area that can do it?

Check you PMs, I will send you something else that might help you out.

   Billy Ray's Haberdashery and Tim Halstead on Facebook might have some tips as well. Billy Ray does some nice work and videos on youtube as does Tim. Not sure where Billy is located but if he is nearby it may be worth it to have him tweek the chambers to lower your compression to work with your current setup.

DCR's from 69* IVC

Static compression ratio of 10.4:1
Your dynamic compression ratio is 8.01:1
Your dynamic cranking pressure is 163.82 PSI

Static compression ratio of 10.5:1
Your dynamic compression ratio is 8.08:1
Your dynamic cranking pressure is 165.69 PSI

unfortunately you don't have any elevation to speak of to help out. i've been using flat sea level.

bumping you up to 1000' makes a difference but IMO you should plan for the worst

Static compression ratio of 10.4:1
Effective stroke is 2.61 inches
Your dynamic compression ratio is 8.01:1
Your dynamic cranking pressure is 158.48 PSI
Your effective compression ratio reflecting 1000' altitude, is 7.81 :1

Static compression ratio of 10.5:1
Your dynamic compression ratio is 8.08:1
Your dynamic cranking pressure is 160.34 PSI
Your effective compression ratio reflecting 1000' altitude is 7.88 :1

http://www.wallaceracing.com/dynamic-cr.php" rel="nofollow - http://www.wallaceracing.com/dynamic-cr.php

Ok, now I understand what you mean about Pence's preferences. But even Rock said to keep the DCR at 8 or lower too.  One thing you have to remember when looking at DCRs from engines like the BOSS 351 and the other high compression engines from this era is they used higher octane fuels then that we don't have readily available today.  I liked Rock' recommendation of keeping DCR at 7.7-7.8 and from his math above the 69* IVC doesn't seem to do it.

I sent you a Google Drop Box download.  Not sure if you got it or it worked?  It might help you with the cam selection.

Now I know where the slight differences in pressure are! I've been using 300 ft. I'm at 450 but surrounding areas dip to 300. Weird going in because I just pulled the altitude out my head for consistent numbers.

I've made two phone calls this week and had rambling conversations with with a guy at Howard's. That cam at 112* LSA gets me to 71 IVC. My only concern there is the .611 lift on the exhaust side without the lifter bore sleeves.

If you pay for a custom cam, the extra $100 gets you control over everything. You set the limits as you want them, and they should easily design a cam to meet them. If you don't want it to open the valves more than .600, you tell them that.

My refresh I'm hoping to use OEM type rockers, which have a general limit of .550", if I can run them to 6000+ rpm or a little more, that's a limit I will set for the cam.

Tell them what you require, it's their job to design it to work optimally within those. If you are having pre-designed cams suggested to you, then those are not going to be the best possible for your engine and vehicle.

http://customfordcams.com/" rel="nofollow - https://customfordcams.com/

this is Brent Lykins cam page, i'm sure he can cobble a cam for you to make it all happen. just a heads-up Brent and George didn't quite see eye to eye. give him a call & rake it over the coals, if Brent's not your cup of tea we can pull a recipe from George's web page. i know there's a hydro roller or 2 in there somewhere and get it ground by Bullet. i'll start looking if i get a chance

a couple hydraulic rollers from George's cook book

69.5* IVC hyd-roller

https://pantera.infopop.cc/topic/looking-for-a-hyd-roller-street-cam" rel="nofollow - https://pantera.infopop.cc/topic/looking-for-a-hyd-roller-street-cam

70* IVC hyd-roller

https://pantera.infopop.cc/topic/camshaft-for-a-great-all-around-street-performance-longchamp" rel="nofollow - https://pantera.infopop.cc/topic/camshaft-for-a-great-all-around-street-performance-longchamp

In the dyno2000 program I took the flat tappet Boss351 Cam and flipped the same specs to a roller cam. That alone netted a 45 Hp / 36 TQ increase. I assume it's just in the projected cam lob profiles. ? 

I did that with the Boss351 cam. Now I'm experimenting......

                                      LIFT              DUR            LCA        ICL         PSI        DCR

George's cam 70* IVC   .544/.544    .278/.286         114        111        160        7.96 

Howard's        67*IVC    .576/.600   .278/.282         112        108        166        8.14

230245-12

Howard's -3    70*IVC    .576/.600   .278/.282         112        111        160        7.96   

230245-12

George's cam    396HP @ 6K       411TQ @ 4.5K   

Howard's  -3     405HP @ 6K       410TQ @ 4.5K

Howards   -4     405HP @ 6K       408TQ @4.5K  

These following are my assumptions based on how I understand what I'm looking at. Please feel free to correct if so inclined. 

Georges cam is 3* advanced                                  114 LSA / 111 LCA     70* IVC

Howard's 230245-12 is 4* advanced                       112 LSA / 108 LCA     67* IVC

I assume if I install the 230245-12 3* retarded        112 LSA/ 111 LCA      70* IVC

If that's the case taking out the whole 4* advance    112LSA/ 112 LCA       71* IVC

Basically losing 1-3 ft lbs of torque in a place I'd never miss it. 

The HP and TQ between Georges cam and a 3* retarded 230245-12 cam are just about identical until you get to 5500 and 6000 rpm where Georges cam falls of by 4HP/4TQ and 9HP/9TQ. Not very important picking one over the other in a street car.  

I find the lift differences and similar power curves somewhat confusing

The previous numbers were based off the Dyno2000 program with a dual plane intake and HP manifolds (they are large compared to most) w/ full exhaust

Large tube headers w/ full exhaust    453HP @ 6K      451TQ @ 4.5K

Add Single Plane                              490HP @ 6K      469TQ @ 5K   

Drop the exhaust                             503HP @ 6K      480TQ @ 5K  

 

 

factor in chain stretch and i think you'll get that 3* you're looking for fairly quickly. me personally i'd target at least that 72* IVC figure i came up with, it'd be a pisser to go through it all and still be on the edge

Not too happy about it now but it is what it is. I'm just as concerned about going too soft as I am too hard. Disappointment is not what I'm looking for in a 17 year project.

How does it look if you retard the Howard's cam 6 degrees so it runs 2 degrees retarded?

This timing set allows for +- 8 degrees at 2 degree increments:

https://www.summitracing.com/parts/clo-9-3521x9/make/ford" rel="nofollow - https://www.summitracing.com/parts/clo-9-3521x9/make/ford

Can you post pics of the power curves?

I had re read your post. I'm likely going to just swap the camshaft but I'm having a lot of fun with the program.

I retarded the cam 8* (in the program!). 

It flipped the cycles on the intake and exhaust. Likely more than obvious to someone who's studied camshafts. If I understand what I'm reading it would likely cause exhaust reversion. The intake closes at 68.3 but the exhaust is closing at 64.3. Most are closing in the mid to late 70's.

It does mathematically look better in the program. 

As it sits   392HP @ 5500 / 426TQ at 4000

8* retard  407HP @ 6000 / 411TQ at 4000 and 4500  

   

Apparently not the way normal people do.....

This is one retarding my cam 8* versus the 235245-12 retarded 3*. Not much difference on paper but the latter has slightly better vol eff.

The latter also has an exhaust cycle 14* longer 

Without dots is the cam I have -8*

The retarding helps but it seems not enough.  From the DCR calculator at 300' it shows:

Interesting seeing the power curves don't change that much between the cams.  What I actually wanted you to try was retarding the Howard's 230245-12 6 degrees instead of 3 degrees as you indicated above.  I think that might get your DCR to a safer range and not affect the power curve too much.  Runinng the Howard's 230245-12 at 3 degrees retarded seem to get the DCR close, so I thought 6 degrees might be right on the money.

Maybe Rock will have a better idea.