I used Egge 10.5:1 pistons in my 273. I was a bit disappointed that the true compression ratio was 9.6 with some milling of the heads but it will be very streetable and pump gas friendly. Who knows what the factory compression really is? I didn't think to check before I took the engine apart. I agree with you. I feel the heads are the most important for building power. You 318 guys can use what ever is available and what your pocketbook can afford. The 273 guys should be happy with reworking the original heads or maybe stepping up to a set of mid 80's #302 castings. Anything bigger on a 273 will be a loss on the street. I am building a +.030 273 with 9.6/1 compression, balanced, with ported heads and a Isky E-4 cam. I am getting closer to hearing mine run. Many of you have read my thread and saw my progress. I won't post any photos here but you can see the progress here.