All things remaining the same, I'm aiming for .440" down in the hole.
The dish is roughly 32.68 cc (I added 4.16 cc for the exhaust valve relief I would have to put in, which brought the total cc to 36.84.) Stroke - 4" Bore - 4.060" (Apologies to everyone following along with the various numbers I was giving. I finally broke out my bore gauge.) Piston to deck - .070" Gasket bore 4.060" was the number I used. Gasket compressed - .060" I used 0 for the head chamber, even though the valves drop in some. Maybe offset by the spark plug divot.
That got me 12.84:1 with what I had sitting in front of me.
If I went to a .125" copper gasket, it would only get me down to 11.82:1
Redid the calculator using 118 cc head chamber, which was a number I found for a stock GM head. It brought me down to the mid 8's? I didn't write it down. So my guess was he started building this motor and acquired the Howard's head sometime after and bolted it on. I'm sure his plan was to go in and rework the block for the aluminum head, he just hadn't got to it by the time Covid started messing with him. So, with all the stuff I have, I'm shooting for some pistons close to .440" in the hole which will get me mid to upper 8's? Plus plenty of clearance for the exhaust valve chase. I haven't decided what to do about cam yet. Even though it's going to have some pretty hefty valve lift, I might try to run it first. Just for giggles.
I figured out who ground the current cam so I might give them a call next week and see if I can't get a cam card. Otherwise, I'm not sure if anyone close by has a cam doctor or similar.
I'll also need to talk to the piston company for recommendations since the combustion chamber would most likely resemble a square round cylinder. Flat top piston, flat head, a lot of flatness going on in there.
I popped the pan off last night even though I don't have it on a stand yet. Rods are 7", the exhaust valve is 1.75" and the intake is 2.125" In a few minutes, I'll run over to the shop and get the stand. I want to get a piston out and see who manufactured it and all the other neat stuff I can see inside. Maybe figure out where the oil pickup sits, how many quarts I can get in this and set the dipstick accordingly. I was also giving thought to ways of reducing rocker ratio. It can be done, but would require 12 rockers and new towers to relocate the rocker shaft.
