Hi Tony,
I would have to agree with RET,
there is not much differance between the two,but a
HP motor is favourable because of the steel crank,
and allegedly thicker bores,which means you can bore them right out.On the other hand,you could mix n match.
I had a 186 bored to 192 with the crank from a 179 HP
block,with TQ20 cam,2.8 blue 12 port closed chamber head,(good compression and 50% more flow
) extractors,350 holley on the varajet manifold in a HR with 4 speed and 336 diff gears and i blew away a few V8's.
So the choices are endless,and the fact that they are holdens makes the whole thing relativley cheap.
CHEERS and goodluck..........BRAD