That's a fairly rudimentary way of judging what is best for your application.
If that 305 has enough power for what you want to do, just run it.
That said, all small block 400s, as delivered by Chevrolet/GM, were never extremely powerful. They were smogger engines, as were many/most engines produced in the '70s, and as such were low output engines moreso tuned/aimed at meeting emissions restrictions.
That said, if you're going to build an engine, I wouldn't so much as think about a 305. I'd either build a 350 based engine or a 400 small block and, at that, a nod towards the latter if you can find a good core to build.
As I referenced by that engine they built in Chevy High Performance, a fairly simple flat-top pistoned 406 small block with a set of as-cast Vortec iron heads, hydraulic cam, readily-available intake manifold, readily-available carb and cheapo headers made 525 lb/ft of torque. That's more power than most stock big blocks make. That would absolutely roach stomp that 305 in your truck now.