273????

The stock 273 hi-po cam specs. are 248 degrees intake/exhaust duration. 26 degree overlap with a lift of .425 inches exhaust & intake. Running a 20-246-4 comp. cams solid unit in my 273 commando that I'm very happy with. http://store.summitracing.com/partdetail.asp?part=CCA-20-246-4&autoview=sku . The 273 setup in my Valiant is as follows & is pretty close to stock with a few tweaks. Good luck with your 273 build. They offer great performance in a light car. Just keep the cam mild like mentioned in previous post.

Oldschoolcuda

stock( 65 block) 273 commando bottom end
Comp cams 20-246-4 solid cam
Mild porting to stock heads
Stock exhaust manifolds port matched to heads
Stock intake manifold with 3/4 inch spacer
Edelbrock 600 cfm carb