WTB small block carb ASAP

Anyways....................
Steve, if it was me I would run a Eddy 600 on the 273 for break in and full time.
For the break in, all you need it to do is idle at Comp Cams specs, for their amount of time.
I like their break in oil as well. In my opinion that carb will be a great match for the 273, right out of the box. If anything, just a little leaning of the primaries with nothing but a 30 second rod change. But any tunning like that can be done down the rode.

Hopefully "THIS" helps. :D