The primary difference is the angle of the bolts around the exhaust crossover. Those center two bolts are not at the same angle as the two on each end.
Those heads are the only ones I'm aware of that are specifically set-up for TBI engines.
I put aluminum heads on my '88 K1500, but I used older-style heads where all the intake manifold bolts are at the same angle. That meant I needed an older-style intake manifold, which then meant I had to do a bunch of adapting and re-engineering/fabricating.
I'd buy the Summit heads if I were doing this again.
Those heads are the only ones I'm aware of that are specifically set-up for TBI engines.
I put aluminum heads on my '88 K1500, but I used older-style heads where all the intake manifold bolts are at the same angle. That meant I needed an older-style intake manifold, which then meant I had to do a bunch of adapting and re-engineering/fabricating.
I'd buy the Summit heads if I were doing this again.