[SD455DJ]

Originally Posted by 67Lemons

As I mentioned above. There are a pair of #62 heads available locally but they have 72cc chambers which would probably be too much compression for the street with my stock pistons in the ‘68 short block?

My current 15’s are supposed to be 75-78cc’s from the factory, will the 72cc heads raise compression too high for pump gas with the stock original pistons in my 1968 400?

Your ’68 #15 heads are listed at 75 cc chambers (10.5 advertised compression) and the ’70 #16 heads are listed as having 78 cc chambers (10.0 advertised compression). My #16’s measured 80 cc’s before resurfacing and 78 cc’s afterwards, right on the advertised chamber size. My 400 is + .030” over, so actually 406 cu. in., with a quench of .040”. The actual calculated static compression is 9.94 to 1. With your std. bore block and factory pistons, probably .020” in-the-hole, your actual compression with your #15 heads would be close to 9.80 with a .039” head gasket (Felpro 1016). Quench would be ok at roughly .060". This would be manageable on 93 octane fuel with a factory style (slow) timing curve and carb jetting slightly on the rich side, along with a good cooling system (temps under 190).

Dennis