good to know.

 

http://351cleveland.wetpaint.com/page/Q+Code+and+Cobra+Jets" rel="nofollow - http://351cleveland.wetpaint.com/page/Q+Code+and+Cobra+Jets

 

the dot or 'Cannonball' first appeared July of 1970, nobody knows why or what it designates. i recall there was a suggestion that it matches dots also found on castings that had been previously cast in Gray Iron w/o the dot, now cast in Nodular iron with the dot but nothing to confirm. as you can see the production run continued with Closed Chamber heads so that's not it

 

http://351cleveland.wetpaint.com/page/4V+Cylinder+Head+Spreadsheet" rel="nofollow - http://351cleveland.wetpaint.com/page/4V+Cylinder+Head+Spreadsheet

 

far as the small valve heads from 1973 & 1974, some guys swear that their virgin D3 heads came from the factory with large valves, could have been a mid-year change for emissions, driveability, or just because they were out of big valves?

 

there's no difference in the raw casting between a 4 bolt or a 2 bolt main block, all castings have the bulge provision in the bulkhead where they get drilled for the outside bolts, only way to know is to look

 

is the air cleaner cover missing? if not, what's the decal say on it?

 

also curious what cam you're getting, any info on it?

 

i found some Erson info in these pages

http://www.osorracing.com/cams/cams.htm" rel="nofollow - http://www.osorracing.com/cams/cams.htm

the only different crank i'm aware of would be the genuine Boss D1ZX-AA crank, it has a slightly different imbalance but otherwise should physically interchange w/o issue just like the others. i wouldn't doubt that the D1ZX crank was spec'd for slightly more oil clearance from the factory also

http://www.network54.com/Forum/119419/thread/1230378948/Boss+351+crankshaft" rel="nofollow - http://www.network54.com/Forum/119419/thread/1230378948/Boss+351+crankshaft -

 

as far as being 2 or 4 bolt, i wouldn't let that weigh to heavily on the decision @ $400

no small valve CJ's in 72, the only small valve OC Clevelands in 72 were 2V's

On the subject of 4 bolt mains, I don't think they increase the strength of the Cleveland block any great amount. My theory is Ford went to 4 bolt to compete with Chevy's 4 bolt. In a GM, the extra bolts do increase strength because the main bolts are smaller than the Ford's. The Ford 2 bolt mains are supposed to be safe to (I think) 6500-7000 RPM's (?).

RV cam = let's wait till you have some numbers

 

for me to keep a clear conscience i need to suggest; 

 

that you replace the rod nuts with new, the stock rod bolts are fine but the nuts fail. miniscule cost & very easy ARP 200-8604 by the 'each', 200-8624 is a 2-pack, or 200-8634 is a 10-pack

and that you  consider replacing the stock valves with new 1 piece units. the stock valve stems are friction welded to the heads. they don't stay welded, sometimes even at idle

 

 

 

http://www.network54.com/Forum/119419/thread/1356932892/what+valves+are+in+this+chamber" rel="nofollow - http://www.network54.com/Forum/119419/thread/1356932892/what+valves+are+in+this+chamber

 

never say never about Ford especially in model year transitions

 

kind of an anomoly with only 208* @ .050" and 280* total, it should pull the lowest gear

set you can find with a stock converter  if that's what you're lookin for? looks to be the same grind as Elgin E-1155-P with 62* overlap, right at about the max for a street Cleveland 

 

rated for 1000-4000 rpm it's gonna run out of wind real fast with any gear much

over 3.00 / 3.25 ~maybe

 

is it a 4 bolt block?

 

D3 small valve heads?

 

there was a Super Stock guy that used to post, he said the small valve heads were the best to start with because they have material in the valve bowls that the big valve heads don't have... a porter that knows what to do can use that material to cause the intake charge to swirl more efficiently through the valve bowls and they make more power than factory large valve heads

 

because of the varying amount of retard of certain valve events, sometimes simply advancing the cam works gangbusters, but with some cams it will palce certain valve opening or closing points too early for the cam to perform properly causing low power or not so hot fuel consumption

 

here's a comparison i did of 3 crank sprockets i had on hand at the time, unfortunately the stock silent type chain crank sprockets have a different number of teeth so a direct comparison isn't possible. all 3 are in the zer0 position, the front & rear sprockets are very close but not the same and the middle one is way different

 

 

 

the only way to set your cam and be sure it's where it's supposed to be according to the manufacturers design, or where you want it to be different from there is to degree it. i got pretty creative with the gear teeth to get one just where i wanted it, because the available -4*, 0 & +4* didn't get me there i started experimenting by skipping a tooth on the chain and using the +/- positions. between the advance ground into the aftermarket cam, and the advance / retard positions in the crank sprocket it can get pretty confusing, here's a pic of the timing set marked with a sharpie and set up in a skipped tooth position. i don't even remember exactly what i did here but it ended exactly where i wanted it. i think i skipped a tooth to retard for 10*, used the advanced keyway and with the advance in the cam grind it ended up about 1/2 of the ground in cam advance for a 108* intake centerline... maybe it was 110*

 

 

the old school way was to use either offset keys &/or drill the dowel pin hole in the cam sprocket oversize and use offset bushing inserts to change the position of the dowel