273 Engine set up I'm thinking of going with, let me know what you think

...It would be a lot of work but it would be interesting to build a true 10.5/1 engine and see how it would run with pump gas. tmm

Indeed it would! If you're using the closed chamber 273 heads, it would probably not do all that bad because flame propagation in such a small cylinder should help temper a little bit of detonation...and you could get away with more cam...would likely be a screamer.