A-518 and 46RH find

Everything I find is about Diesel applications which is probably overkill for a gas engine … even a 500” 600 ft-lb build . Diesels come on much more abruptly than gas .
As for the Barracuda trany I want it to handle up to 400 hp and be reliable. That may only require a rebuild kit with good clutches and some fluid flow mods. This trany has 4 pinion in front and a 3 pinion in back . Good enough ? I dont know … And I dont beat on my car … much …lol