I agree on the 273 heads except the hardened seats. Really not needed for a light car that going to light driving and no long towing. I've had 273 heads without the hardened seats and no problems. One thing to remember,the 273 2bl motors were rated at 8.8 to 1 Cr. With a little machine work and a .028 felpro you can get 9.1 to 9.5 cr with the flat tops depending on how much meat you take off the heads and the deck. I am getting ready to do another 273 only this time i would like to find some forged 8.8 2 bl pistons. They are out there, just have to find them. $475 for the L2222 from Huges is a good deal