273 Cyl Head Differences

waddney said

I've been chasing a set of heads for my build with the casting number 2658920, I have found a set casting number 2465315, are there
any differences between the two, I was told that the earlier style uses different intake bolts (smaller diameter) and at a different angle,
the heads are a distance away so I don't physically have them to compare

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920 heads are 67 heads that use the standard 3/8 intake bolts that have a 9/16" hex head. 315 heads are typically 64-65 heads that use 5/16 intake bolts on a different angle that have a 1/2" hex head. However I have a set of 315 castings that use the standard 3/8 intake bolts that have a 9/16 hex head. Not sure what was going on but appear to be virgin OEM heads. They even have the steel shim head gasket witness lines from the original .020 thick 273 head gaskets. Best advice I can give is to ask what size bolts those heads are tapped for. There are 66 heads that will interchange with the 920s and you can also use any 318 heads with a slight loss of compression.