whats the difference between these two engines? Did it have anything to do with emissions?

 

L03 is the TBI (Throttle Body Injected) 305 (5.0L) as used in GM F-bodies (and B-bodies and trucks). In our F-body applications it has a roller cam, and swirl port heads that emphasis low rpm torque in favor of higher rpm breathing (perfect for a truck engine, or moving a large B-body Caprice, etc.). They make 170hp.

L30 is the VORTEC 305 (5.0L) cousin of the L31 350 (5.7L). Never a car engine, used just in trucks. It has a roller cam, a funky multipoint injection system with somewhat restricted plastic intake, and superior VORTEC heads which flow well for a factory iron head. Those that I have seen (L30 and L31) have twin "y" pipes feeding twin cats as well. Horsepower was 230.

The L30 may run marginally cleaner from an emissions point of view, but this is largely the mid-90s chase for more torque and horsepower.

 

If I wasnt such a weight ****, I'd love to use the L30 heads and an LT1 cam in my current 305, but.... if I'm swapping heads then aluminum is what's going on. That combo with 1.6 rockers and some tuning would make for a fun 305 for dirt cheap.

 

I agree Robert. I'd have liked to have found a good deal on a set of L30s before I went another direction. Oh well.