33417369...90-up...350..........Gen.I Goodwrench crate motor,"Hecho en Mexico", 76cc
So open chamber heads, so with FT 4 v/v relief pistons and tin shim head gaskets you might just squeeze 9:1 compression out of it. Big chamber with spark plug location low in the chamber close to the piston = an inefficient smog head at best, the only saving grace these heads had is that their NOX emissions were lower. any motor these heads are on will be a gas hog. The best Mpg i ever got from my striped down 78 Blazer runnin a 350 with 882 castings (same head) after RV cam, headers, leaned out Q-jet, head work, ignition, super tune was 13 mpg ! Whatever your plans for that 350 are, better heads are gonna need to be part of the equation ....