Tempest-T37 here is a easy way to figure out the total number of CCs you need to achieve a given compression ratio.
To do this you need two things, one being the total CCs of your .030” over 350 with the new 4.250” stroke.
When you run the numbers you get 51 cid per cylinder, for a total of 408 cid.
We need to convert this CCs so we Xs that by 16.387.
Now you have your cylinder volume in CCs which is 836.2 .
Now let’s say you want to end up with a 9 to 1 compression, to get this answer we subtract 1 from 9 for the result of 8.
Now simply divide 836.2 by 8, the result is that when the piston is at TDC you will need a total CC volume of 104.5 to get your 9 to 1 compression.
If you where looking for a 9.5 to 1 compression you would need a total CC volume of 101.5 .
Some things to take into account when figuring out your compression is adding 1 CC of ring land volume for your size bore and also that some head gaskets like the common Fel Pro 8518 and 6014 is the fact that these do not have round bores, that are oval, so they contain more CCs then if you figure out there CC volume with just the bore size.
From what I show here you can safely assume that every 4 CC change up or down will change your final compression ratio by 1/2 a point,
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Last edited by steve25; 11-23-2021 at 07:11 PM.
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