I ran a 454 in my 40 back in 2001, was 440 rw hp running 36" swampers, 60 t case and gearbox, 4 wheel discs, and 75 power steering, we made it 98" wheelbase, and widened the track with 60 housings and offset rims as well, and it would still wheelstand in first on the road, and wind off the clock with 4.11's and 36" tyres with 10 psi in them, [rough calc 200kph or 120mph] I ran qjet big block buick carby, and it would give 16lt per 100km [25mpg US aprox I think] hwy cruising at 100kph [64mph] with the 4 speed.
Had hand made extractors and 3" exhaust on it, with straight through muffler, as big blocks arent loud.
It would also lug along at 400 rpm, while I dragged the brake, for wheeling slow, or in the snow, to get up on top of it, in 1st low, or 1st or 2nd high.
I ran all 40 drive train [apparently the cv's are week, but Ive never broken a cv] except 60 4 speed gearbox and t/case.
I ran a custom alloy radiator, hand built shroud and a big statesman fan, which pull 22% more air at idle than a standard viscous fan at the time, never got hot.
just finished some work on another which has motec injected 502 big block in 80 chassis with 75 series body, which is 440 rw kw [600 hp] and 1000 rw nm, and with correct radiator and fan, it doesnt get hot either, and runs 80 running gear with nissan patrol front centre, with 80 outers.
We are currently also building an 05 TJ with ls 1 and l60e auto, which has patrol diffs, and brakes, and 12" fox coil overs, but even with hand made exhaust, it doesnt sound like a big block.
Nothing sounds like a big block!