273 piston options

360DartGT66 said

I have a set of 360 heads and I’ve considered using those. I’m aware of the notching/shrouding issue but I think perhaps the increased flow capability compensates for that. The chambers are much bigger though so domes pistons and perhaps some cutting on the heads to get to a reasonable static compression.
We have E10 gasoline at 95 octane as well as E85 over here in Sweden and some stations sell 98 octane.

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If you mill 360 heads .040 and .038 on the intake side of the head you can get the chambers down to 64.7 cc. I've run them on a + .040 bore 273 and it was amazing, pulled to 7K no problem. No bore notches, but I did make sure the chambers were centered on the bores with offset dowels. But in reality, I think early 273 heads flow almost as much as 360 heads with a little clean up. I second your idea of a solid flat tappet cam. The limiting factor will be the valve train, take the time to set it up as well as you can.