I have a 402 from Texas-Speed with -10cc pistons and 64cc chambers.

How much "down in the hole" is the piston at TDC, and how much volume would that displace? Lets call this Vdh.

Also, I need the volume of the head gasket. Lets call this Vhg. I do not recall the thickness.

So far I have:

CR = [825 + 10 + 64] / [10 + 64] = 12.15 which is way to high.

However, I need the following:

CR = [825 + 10 + 64 + Vdh + Vhg] / [10 + 64 + Vdh + Vhg] to accurately calculate the static compression ratio.

 

I estimate the compressed head gasket volume at 7.2 cc if the compressed gasket gauge is 0.035". What do you guys think?

 

I got 10.88:1 CR assuming:

4.005" bore and 4.00" stroke (825.91cc)
4.030" x .051" gasket (10.66cc)
.005" out of the hole (-1.03cc)
64cc chamber
10cc dished piston

 

So these LSxs are "out of the hole", not "down in the hole" 0.025" like the SBCs?

Thank you for the reply.

 

Typically they are out of the hole ~.007" stock. TSP seems to use GM MLS gaskets on their longblocks, which are .051" thick, so I am assuming they do the same. You should have a build sheet that came with your engine to tell you all of this, or TSP may have it on record for you if you contact them.

 

I have TSPs build sheet for this short block. Being a short block, there is no mention of head gasket thickness. I can not remember what I used, but they were highly recommended at the time, which is now 2 years ago.

KCS: I believe that you have given me the missing volumes. Thank you.