I am doing a build where I need to get thecompression up around 11 to 1. The piston/cylinder combo being used will get to10.7 to 1. Does anyone know how much more a 0.030 head gasket will bump it up?The cylinders are also being zero decked. I'm hoping the combo will get me to11 to 1. Thank you!

 

what size gasket was figured in the 10.7-1? heads can easily be milled from 10.7-1 to 11.0-1. where the heads cc`d?

 

An .040 gasket advertised for the 10.7. The ratio was also for 95cc heads. I've had work done and believe mine are at 96cc. Wasn't sure if that was enough to bump it back down some.

 

Going from .040" and 95cc chambers to .030" head gasket and 96cc chambers is "treading water". Use the link to see how much you need to deck the heads to hit 11:1.

http://www.bigboyzheadporting.com/TwinCamComp.htm

 

Thank you, I will check that out. I'm assuming you mean the difference between both combos is pretty much a bust, 10.7 either way?


I'm just east if Cincinnati, I'll look around for someone to do a little head work if needed. From what I am understanding by the link, going from 040 to 030 will bump it up about .2 on the compression?

 

Also keep in mind (as I found out the hard way) that cam choice will affect your CCP.

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You may already have this covered so my apologies if so but.....With the mods to deck height and any milling of the heads and thinner HG be sure to keep tabs on your piston to valve clearance. Including any cam changes that may effect the timing of the valves which may cause the two to collide just the same.

 

Yes, if chamber volume doesn't change. What I read from your OP was that the 10.7 static was generated with 95cc chambers and a .040" head gasket but the change to the .030" head gasket would be with 96cc chambers; maybe I read it wrong. My calcs show a .14 increase in static if the chamber volume stays at 96cc in both calculations.

 

Thanks for the last few comments, I'll definitely have my ducks in a row before going nuts on the build. I'll have some expert help as well.

I did the calculator on that link provided. Set it to 117, 030 gasket, and changed the piston dome from -1.5 to 6.6cc, 96cc heads, and left all other numbers the same. It's calculating that setup at 11.02 to 1. Hopefully that's accurate!

Thanks again for the replies.

 

It is pretty accurate. Did you allow for deck height?