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These calculations based on 30 over 440, stock stroke, 84 cc head, flat top piston no valve reliefs nearest piston to deck is 0.068".
Mopar machine work wasn't the greatest and I'm betting your decks are not square to each other or parallel to the crankshaft centerline.
A 30 over 440 has about 914cc swept volume. We would like to have 10.5:1 compression with aluminum heads. To find the volume above the piston required for a compression ratio "r", divide by the quantity (r-1). 914 / 9.5 = 96.2cc. The head volume is 84cc so you need just 12.2cc more than the head. A normal 0.040" composition gasket is about 12 cc so you can see you need to delete some volume somewhere. The steel shim head gasket is 5 or 6 cc so let's say 6. Quite a few guys on this board have used them with success.

So your closest piston is 0.068 in the hole which equals 914 * 0.068/3.75 or 16.6 cc. I suggest cutting 0.035" down from the lowest corner so now all the pistons should be 0.033" down in the hole. You now have 914 * 0.033/3.75 or 8cc which plus the 6 cc of the head gasket and the 84cc head gives you 98cc. (914 + 98) / 98 = 10.3:1. I'd live with that. If you think about it you'll see that milling the block is twice as effective as milling a closed chamber head.
If you use just the steel valley pan/intake gasket with a smear of Hylomar around all the openings the intake should bolt on OK. Then all you have to worry about is valve to piston clearance.
Use checking springs with the valves on one cylinder and check the V/P clearance every 5 degrees from 20 BTDC to 20 ATDC and see what you get. One of the cam manufacturers has the procedure posted.

With 0.052" squish clearance your engine will run very well.
Good Luck!
R.




Thanks a lot Dogdays for all the work that this text involves.
Those formulas are very interisting and useful.
Couriosly ,is the typical theoricaly part that you find boring until you start to find troubles .

To mill the block sound even worse than mill the heads,however i,m starting to belive that this block could have been milled yet,cause i Googled the pistons part number(L2388) and i found a few posts wich talk about people who have used these pistons on 440 blocks and they sit even deeper than mine,such as 0.080 to 0.12 deck.


Last edited by Coke; 02/15/12 04:14 PM.