I have found a couple of Calculators on the net.. I am trying to get my 402 L76/L92 setup to around 10.5:1 Compression. As far as I know the factory L92 Head Chambers are 70cc, then 4.000 Bore/Stroke, the Pistons I am looking at are 12cc Reliefs. The Deck Height is the one that I don't have, it's a 6.0l Iron Block.
I want to mill the Heads down about .020, to bring then down to about 66.8cc Chambers. The Cam is 237/242, .603/.609, 112LSA.
I saw the list of Head Gaskets in the other Thread, can anyone throw out some more info that might help me out, like any setup that you might have that comes close to what I am looking for.

 

If you mill the heads to 66.8 and run a .040 Cometic your compression ratio should be 10.60:1.

I had to slightly change the cam lobe as it is not listed as a Comp grind, but here is what I came up with:

238/242 .605/.609 112 lsa +0 SCR 10.6/DCR 7.76, and that is with the -12cc pistons .006 out of the hole.

Is your gas quality limited as the SCR/DCR could be raised to increase the overall power/response of the engine? I would go in the 11.5:1 SCR and 8.4+ DCR....

Good luck!

 

Thanks. I must have been using the wrong Deck Height. Are the LSX Engines pretty much close to a 0 Deck Height? What can be done to get it a little higher SCR, and how do you figure out the DCR?
That Cam is the TX Magic Stick 3.

 

Either run a piston with less of a dish or mill the heads more, but watch the L92's as I have heard a PTV issues...

Possibly look into a -2cc piston?

Let me work that out.

 

That's another thing that I have to look into, how to setup that system. What have you heard about them?

 

Pistons usually come out of the bore about .007-.010". If your calculator can't do that number then enter it as a .007-010" thinner gasket to get the same results.

 

Really.. these Engines they actually come up a little bit? I did not know that, I am used to the Gen I/II's..