I also posted this in "The "Other" Bench" without any replies...hopefully I'll have better luck here. On a 440 Mopar that is pump gas friendly or very close (approx 10:1), what is the typical deck height and head gasket thickness? Thank you in advance.
Well, I'm helping a buddy lower the compression in his engine and the question of quench came up. Some say 0.040"-0.050" is ideal but another buddy said he thought 440 Mopars had much more quench than that, around 0.120". The actual application is a 455 Buick, which is very similar to a 440. Before any aftermarket heads were available for a Buick, B1 heads were redrilled (head bolts) and used on 455's. Also, the 455 is swirl combustion, I think 440 is and I'm told quench is most important in tumble engines (like Ford). My reasoning is if a 440 has as much quench as my buddy said, then adding a thick head gasket to the Buick should work and hopefully not affect octane requirement. Clear as mud?
Yes, clear as mud is right. So are you building a Buick 455 or a Chrysler 440? Trying to build one with techniques and parts from the other is just asking for trouble. If you are trying to figure out quench then your are doing the actual work to measure the combustion chamber volue of each cylinder and get actual C.R.-Correct? And which Head gaskets are you using as your reference for thickness? IIRC, there area about half a dozen different gaskets for differenct 440's. Please clarify.
Rob Ask Motorman on this Board. Few have had his years and depth of experience in such engine issues.
Maybe this is an easier starting point...what was the deck height and head gasket thickness of a 1970 440?
I recently sold a 69 440 block to a freind. This was the first motor I built. It was not decked. Should be exactly the same as a 70. I will give him a call tonight. As I recall the Mopar Engines book says the 72-78 pistons are lighter than the earlier because they had a smaller compression height and lowered the compression. I did measure a 73 a while back (for a freind who bought a cuda from someone in MI that mentioned your board name) and it was .085-.090". These fact. pistons are flat/no dish unlike a Buick. Factory steel head gasket thickness is .018-.020". Ray
Supposedly the 69 piston is not the same as the 70. The heads are the same but in 70 they used the 67 piston to lower the comp. a bit. The 68-69 used a higher compression height piston when Chrysler went to the 906 open chamber head to bring the compression up. Too many variables. From info I gather. the 67/70 and 71 approx. .090" in the hole, 68/69 approx .050" 72-78 were all over the place. .080-.120" in the hole, some even say .150". You are best off to measure yourself. Ray
The actual application is a 455 Buick, which is very similar to a 440. Before any aftermarket heads were available for a Buick, B1 heads were redrilled (head bolts) and used on 455's. hoooooooo-leeee crap. :shock:
The 440 is part of the RB family in the Mopar world. What you are doing is a MOOT POINT. You can gain everything you are trying to do simply by advanceing the timming on the 440. If you increase the thickness of the head gaskets on the 440 that big square thing the the carb sets on called a manafold will not seal up good and tight to each side of the head. By rasing the head off the block the angle of the mateing surface of the intake is changed. Not trying to be rude, but rethink the idea, you are doing some major work with no gain, just pain. Now if you change pistions remember in the Mopars all stright shift cars had a steel-cranks and the auto's usually had a cast-cranks. The motors are externally balanced.
