1965 273 Heads

PolarBear said
Okay.... I'm convinced - heads are heads (at least in this instance).

Laysons has 273 Commando pistons - as factory replacements, and also in 30 over and 40 over - but Layson's is VERY overpriced (with all their parts, typically).

And I had wondered about the octane business, too. With such high compression in the Commando engine, you'd probably be faced with adding octane boosters each time you filled up.

Anyway, I'm really not looking to build a racer............. but someday, an upgrade to a 340 would be cool.

The question is do you really need to rebuild the motor. With the CR at about 8.8 to 1 about .011 in the hole. All it would take is to shave the heads about .020, a head gasket change to .028 orange gasket and you'll be in around 9.2 CR. There are a lot of cam grinds out there specificly for a small displacement motor in a light car. As far as intake and carb the Edelbrock D4B with a Carter 625 would fit the bill. Exhaust could be handled by the TTI's or Spitfires.