Highest flowing sbm heads?

DionR said
Add that the G3 and LA share bore spacings, and the deck of a G3 is a touch shorter than an LA. Also, the first G3 used a 318 bore size with a 360 crank stroke to get a 5.7 displacement. Might not have parts that interchange, but the G3 has little to compare to a BBM while it seems to have at least been based on the LA.

And a displacement cutoff of 400 doesn't really work since there is a 350 B motor. Seems like the better criteria would be bore spacing and deck height when compared to other motors of the same brand.

Regarding the 350, true. But I reference actual block size. If it's a bigger block than the small block, it's a big block! Lol
I qualified it to remove comparisons of displacements to engine families that only have one block. A 408 stroker is still a small block, a 383 Mopar is a big block, a 383 chevy is a small block, a 400 small block chevy is a small block, a 396 is a big block etc.