Hello all,

I have a rebuilt 400 030" with sealed powered 427NP-030 pistons,chrome moly rings,comp cam extreme energy 268 series timing chain/lifter/springs/retainers on D5AE-A2A (74.5 CC) rebuilt heads with perma-torque fel-pro head gaskets.I don't how much the deck or heads have been killed since I bought off of someone.It will have a Holley Street Dominator intake (300-20) with a 650cfm Holley carb and 1" spacer. Hooker Super Comp headers and 2-1/2" exhaust with a cross over pipe. Mallory Unilite dizzy(for now) Accel Coil.

 I'm having trouble figuring out with the compression ratio is with this combination? I'm thinking about 8.8:1? Im hoping 300-350hp about at the crank?

Also

Big Bird wrote: Did the 351M have a flexplate? Should be the same.

it has one but the motor that is still the car and I'm driving it until I'm ready to pull it out. I'm reading through the aftermarket that the 351M/400 uses the same flexplate. I'm just concerned about vibration/balance issues. My current in car set up shakes but it could a number of things not addressed atm.

ok I'll check it out, thank youl

 

The C4/FMX uses a different offset than the C6.  Using the FRA-201 with an FMX will result in too little clearance.  There is a 351M/FMX specific flex plate and it is D3AZ 6375-A.  I can't find an aftermarket cross reference to this, but Mac's has one for a decent price here:

 

https://www.macsautoparts.com/ford_fairlane_torino/flexplate-351m-fmx-trans.html" rel="nofollow - https://www.macsautoparts.com/ford_fairlane_torino/flexplate-351m-fmx-trans.html

 

Based on my research, a FRA-205 *should* work too.  It is a 28 oz imbalance and has the correct offset for a C4/FMX transmission.  But for whatever reason, there is always a specific flex plate listed for the 351M/400 alone, even though they have the same imbalance.  So, for example. a 351W with a C6 should use the same flywheel as a 400 with a C6.  Same imbalance, same offset, but there are two separate part numbers listed for each application, aftermarket and Ford.  I even compared a OEM 302 C6 flexplate to a 400 C6 and it looked identical, bolted up and fit exactly the same.  So, like I said, a FRA-205 should work, but there may be some other minor difference I am not aware of.

 

What ever you chose to use, just make sure you check the TC clearances as you bolt everything up. 

 

As for your 400, where are you getting the head volume of approx. 75 cc?  It was my understanding that all 400 heads, the D1 and D5 castings, were about 78 ccs?  Also, from what I have read, those rebuilder pistons will produce about 8:1 compression at best, maybe even less.  Rockatansky might chime in as he'll know more.  But the bottom line is these pistons produce really low compression.

 

If the engine is out of the car, it might be worth your effort to upgrade the pistons.  TMI has 9.3:1 hypereutectic pistons that are designed to work will with the open chamber heads.  The also drastically reduce the excessive deck clearances of the OEM/rebuilder style pistons.  You other option would be to run 351C pistons, but they'd have to be bushed to would with the 400 rods.

 

If you get some decent pistons in there, with that cam, this will be a strong engine.

according to the factory part number D1AZ 6375-A (current replacement part number) works on all 351M/400 cars and trucks. (per Bubbas 351M/400 website)

I found part numbers through Pioneer FRA-20, FRA-202 and FRA-205

ATP brand Z-106 http://atpautomotive.com/flexplate-z-106

the 351M Heads cc specs I got also from Bubbas website. Maybe Ill put some Aussie heads on it?

 

 

 

I think you're better off to replace the pistons than the heads.  TMI just got a shipment of new pistons.  Call him up and leave a message and he will call you back.  The heads you have on there are fine for your build.  Aussie heads are hard to find, they don't have the best flow numbers and you still have a pistons that have terrible deck clearance, which can lead to detonation problems.  I think you'll have a 350+ hp engine with the TMI pistons, and boatloads of torque.

If that is the case, then the 351M 'plate is the correct one to use.

7.9:1 it's on crutches from the start

https://www.jegs.com/i/Sealed-Power/844/427NP30/10002/-1" rel="nofollow - https://www.jegs.com/i/Sealed-Power/844/427NP30/10002/-1

power & efficiency start with the internal engine

I would like to go that route, but it would be a pain to take it all apart and have it re-balanced and re-assemble it.

I might just go that route if the flywheel ring gear is in good condition.

eutectic alloy is old school cast, slightly better than hypereutectic for durability but still by no means a performance rated piston. hyper-U has more silicon content causing them t be brittle and expand less than lower silicon eutectic alloy. 2618 is the old school forged alloy, relatively soft durable as  and expands like crazy. hi-po applications need enough bore clearance that they'll slap until they warm up ... 4032 is the low expansion darling of the forged piston world, actually a forged hyper alloy

https://www.hotrod.com/articles/narrowing-your-piston-choices/

great info, thank you!

With those new heads you should be at about 9.4-9.5:1 compression. So your engine should make really good power with that cam.  You sure it's an XE268 and not a XE262?  The only one that's been made is the XE262 in the past 5 or 6 years that I have been checking.

 

The only thing you may have to worry about is detonation.  Those stock pistons style are pretty far down in the hole, which can cause this problem. Maybe Rock can offer more input on that issue.  

 

TMI even has new pistons for Aussie headed 400's too.  It yields about the same compression ration as stock pistons, but it has far better deck clearances to eliminate the detonation issues.

 here are some pics. Theyre 302c heads.

 

I stand corrected, it is the 262 extreme energy cam. Ill have to be careful on the timing and advance curve once i get it going. Thank you for insight. 😎

with more guessing than i usually need to do, i'm coming up with 9.75:1 static CR

and right on the ragged edge of pump premium with 8.07:1 DCR

Yes with a CH of 1.630" IIRC the pistons are down in the hole, i guesstimated .080" for the calcs but it could be more? more is better for DCR and octane requirement. elevation will also relieve the squeeze, how far are you above sea level?

125' feet above sea level.

not what i'd call elevation. for a worst case scenario i'd look at what it's doing at -500' (below sea level) for margin. the difference may not be enough to change the build but good to know where your at vs the ping monster. like i said up above too many swags IMO, i cant find a dish volume for the 427NP pistons. they give the dish dimensions easy enough to calc & add maybe 2cc's for the reliefs for total volume

if you have an original 400 balancer you should look at having it rebuilt,

real 400 balancers are heavier than the 351M unit that superseded the original part number

unfortunately the new motor didn't come with one and the engine in the vehicle is a small diameter 351m style...

Pioneer lists a DA3512HD

https://www.summitracing.com/parts/pio-da-3512-hd" rel="nofollow - https://www.summitracing.com/parts/pio-da-3512-hd

I picked up this unit the other day, thank you sir.

So I would like all of all your opinions on another matter. I bought the 400 off of a private party. It's 80% built, crank,cam,lifters,rocker arms,push-rods,water pump,timing chain,intake on(which I will use my own intake) heads on(which I am also changing) 

I want to go over all the side clearances for the crankshaft,rods and make sure the rear main seal is properly installed, it was sitting for awhile before i purchased it. Should I remove the bearing caps and re-lubricate the main bearings?

let us know what you get

I got the pioneer one from summit, it looks like a stock replacement unit...nothing like the one in the picture used though. but it was on sale for 99.50 so it qualified for free shipping.