6inarow, has you headed in the right direction. I think what it comes down to is what is "a little punch". You can build a 250 for less than the 292. You save yourself a bunch in just the pistons. You can use 305 pistons for the 250 and get some decent compression, were as with the 292 to get to 10.0 compression you will have to go forged. A 292 does have the cubes and a stock 292 will have the torque of a 350 on the bottom end. These motors will require some mods to bolt in.
Then a 261 may provide "a little punch" and would be almost a bolt in. I would also search stovebolt.com there are quite a few folks there with the 50s trucks and cars and 261, 250/292 are all popular.
Larry
