I’m not up on what the costs would be for any sb or g3 build at that level, but that power level wouldn’t be that hard to reach with an LA these days.

Victor heads, Ritter block, and Brett Miller has a killer new intake manifold that has already been tested at north of 900hp on a low-400” build with a cam that’s not a parts killer.

If you know what to do with them, the G3 is probably the cheapest.