A 400 small block would suit your needs to a "T" IF you can find one that will clean up at 0.030. They just can't take much overbore. A second option is a 377 or 383 stroker kit which one can find on ebay for as little as $400. This gives the longer 400 stroke in a much easier to find 350 block. For your app a cam that was near the same specs as the the one for a 366 big block would work good---all low rpm torque. IIRC (no guarantee) I turned some front bearing retainers down to fit the smaller bell housing hole. Had to use socket head (Allen head) bolts that may have been shaved a bit. You just need the left side 265 manifold. With the flat log type exhaust a 2bbl carb would handle all the induction one needed. A Rochester from a 455 Pontiac or Olds would work good and are reliable with easy to find parts. Our tow vehicle for years was a 51 GMC with a 500 Cadillac engine and it was great so I know big cubes and a long stroke works. The V8 choice for you is the right one in my opinion.
