Intake manifold gasket differences

[dr deuce]

There is a big difference between the intake-exhaust manifold gasket sets between the WW2 270 and the later (50's) 270 and 302 as shown in the picture here.

[R Cubed]

There is quite a difference between the two of them, did the later 50's 270 head and the 302 head have the same inlet / exhaust gaskets or were the heads the same too, as in the 50's didnt the 270's go over to flat top pistons so the heads would have had to be different to keep the compression ratio the same ?

[dr deuce]

I "believe" that the 50's 270 and 302 both had the flat topped pistons and large ported heads. I do know that there are 2 different 302 manifolds; one with round intake runners and one with flatish runners. That is the difference between the 4 bolt Stromberg carbed engines and the 3 bolt Holley carbed engines. The 4 bolters have a fatal flaw in that they crack in the carb heat box area under the carb and pieces literally fall off. This is the area that has exhaust gasses in it to preheat the intake manifold just under the carb for better fuel vaporization. The common fix is to weld the manifold so that there is no box under the carb and hence no exhaust leak.

I also know that the 302 has a different head gasket tightening sequence. I have never seen an engine with one like this. One circle around in the middle as usual then up one side to the end then back on the other side of that end across the middle and up and down the other side to the middle again.