You would have to buy Cometics at only .027 for $195 plus ship. Cometics also require a particular deck finish to seal correctly. These are perfect for 71 engines in that they will obviously work with the early coolant ports, will bump the comp up a good bit especially if you kill the heads .020 you would get close to 9.5 to 1 perfect for 93 octane. With a 70 engine you would restore the original 9.8 to 1 comp at a minimum vs dropp8 the comp with the standard. 040 gaskets. Then of course if the heads were milled you could potentially achieve a true 10 to 1
Did this on my 71 motor. Stock bore, stock pistons, undecked stock block, Felpro composites, my compression ratio calculated to be 8.2:1. Swapped in TA1607 stock bore "10:1" pistons and steel shim head gaskets, and my measured, calculated compression is now 9.5:1. The pistons got me .010 closer to the deck, and the steel shim gaskets got the heads .020 closer to the deck. Now have about .050-.055 quench, before was about .080. Ran a 13.57@102.7 at this year's Nats with stock heads, manifolds, and a TA288/94 cam in a 1966 Skylark. Hugger is right, steel shim head gaskets should gain you about .5 more compression ratio over Felpro composites. TTT for Hugger.
Hey Hugger this is more of a question than getting in line but I have a 70 455 block with 68 430 heads (that oil through the pushrods) that I'm building would these work or would I have to use the 430 steel shim gaskets?
No you need the 455 gasket, tbe 430 gasket bore isn't big enough and may protrude into the bore, a .030 over 455 is 4.34in
Thank you for the response. That's what I figured, to bad I can't afford these right now! Good luck with the sale!
