New Member - 360 Tips, Suggestions

The only problem with them calculators, is that they are sea level calculations.
There are a couple of compression calculators on line that have a Altitude option you can add that helps a lot for us thin air breathers:cheers:

My 340 compression check went from 160-170 psi at 4000 foot to 130-140 at 7000 feet.
Nothing was changed but the drive!!!!!!!

You can get a way with a LOT more compression at that altitude.

The most important thing to look at, when doing a compression check is even of the compression.
If those compression ### would have had a 90 psi mixed into there then i would have be worried.

Do you have flat top piston or dished?
are you sure there not down in the bore .020" or more.
and last, i would bet the head cc"s are closer to 72cc then 65cc.
My heads were 74CC(340 X head)

One last note: High altitude likes more ign timing!