identifying heads for 273

72 Demon said

IMHO the best course of action, particularly if you are planning to rebuild the engine, is to install the flat top (2 bbl) pistons. If no rebuild is planned, try the thickest head gasket you can find. (Don't know if you can double up head gaskets on the LA). The advantage of these options is that there is no need to alter bolt hole relationships.

The flat tops are a lot easier to find than the domed pistons. I would be very hesitant to do anything to the HP pistons beyond new pins and rings.

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I'd be carefull of this. My rebuilt 273 2 bbl cc'd out to 7.7 to one compression. Heads were 65cc and pistons .045 in the hole. I had to mill the heads 30, and the block 40 thou to get 9 to 1 out of it. Now its 60 cc heads and .005 in the hole. Using a .040 thou gasket and ending up with .045 of quench.
The pistons were new so I just decided to see what I could do with what I had. Ideally I would have gotten dome pistons. But theres a 340 sitting in the corner taunting me, I'd rather spend money on that.