i baught a rebuilt 350 motor and it looks like it is set up for marine standards. it has a carburated intake and it looks like it has the old heads on it from like the 80's also it has a mild cam in it. does anyone know if those old heads are better. i was thinking with going with 5.3 vortec heads. would that also benifit me?

 

Pound for pound the vortecs flow better.

 

What year engine you think? Centerbolt heads?