Rebuilt 302 casting heads available through Rockauto
It depends how high your pistons are sitting in the hole at Top Dead Center. The prefered 69 318 factory valve relief pistons sit .045 ths down in the hole, this is about the best stock piston you can get for the 318s but are in short supply. With the 302 heads and the thinner smaller diameter head gasket you run real close to 9.5:1 compression ratio as an example.
Next best piston choice for the 318 is the 93 Ram Truck 318 flat top piston they probably sit .070 down in the hole but don't have the valve reliefs so that helps compression some too. Around 9:1 give or take.
Think the 67 273 probably had pretty good compression for back in the day, so the 302 heads should help them a lot. ToolManMike did a 273 build with the original 67 Closed Chamber heads, might want to see if you have these heads already on your engine. ToolManMike would be good for more info if you need it too.
The new Reman heads: 302, 646, and 714 castings are all the same head. Better Ports and Port Flow than earlier 318 factory heads.
69 318 Factory 230 hp engine, 340 camshaft, 302 heads.
Have fun with your 273 . . .
It depends how high your pistons are sitting in the hole at Top Dead Center. The prefered 69 318 factory valve relief pistons sit .045 ths down in the hole, this is about the best stock piston you can get for the 318s but are in short supply. With the 302 heads and the thinner smaller diameter head gasket you run real close to 9.5:1 compression ratio as an example.
Next best piston choice for the 318 is the 93 Ram Truck 318 flat top piston they probably sit .070 down in the hole but don't have the valve reliefs so that helps compression some too. Around 9:1 give or take.
Think the 67 273 probably had pretty good compression for back in the day, so the 302 heads should help them a lot. ToolManMike did a 273 build with the original 67 Closed Chamber heads, might want to see if you have these heads already on your engine. ToolManMike would be good for more info if you need it too.
The new Reman heads: 302, 646, and 714 castings are all the same head. Better Ports and Port Flow than earlier 318 factory heads.
69 318 Factory 230 hp engine, 340 camshaft, 302 heads.
Have fun with your 273 . . .