So just how good are these SBM engines

Hp guess, around 400hp. The smallblock mopar is a very reliable engine. From what i've seen the 360's are a little harder on the main bearings than the 318/340 2.5 inch mains.

As said by rumblefish oiling mods are very important in the sbm. Them stock rods will live along time, mine are 1970 340 rods that have had the beams polished and shot peened. Been used as race engine since 1989 at around 450hp. Keep us posted on your results!