‘72 engine swap

[Muzzy5.0]

OK, so I’ve recently come back to C10’s and bought a ‘72 long bed with a 307 and 3 on the tree. Long term plan is to replace the 3 speed with a 5 speed. But before that I need to sort the engine.
I like the idea of building the 307 a bit, intake, carb, heads a bit of a cam etc. Nothing too crazy (especially with fuel prices over here ) but ..... there’s a guy got a 350 out of a truck (88 - 95 according to the block numbers apparently). Obviously it needs an intake and carb and a dizzy, am I right in thinking this is a Vortec lump ? Is it any good ? Will it mount up to everything else in the truck ? I guess it will need a mechanical fuel pump too ?
Finding a pair of heads for the 307 is not so easy in the U.K. and getting brand new small chamber heads with small enough valves shipped will be expensive.

Thanks in advance ..