454 mildly built, held up great, soaks up less hp too than the t400. Coming out this spring with total rebuild 30 over full roller and had the t350 built to handle the extra trorque. Running 3200 stall from trans specialities, was trying to run bm holeshot 3k but it runed out to be junk from the factory. Car runs 3.73 with ladder bars and I put many miles on the old t350. Never down the track but drive it like hell regularly.