RLSH700

That is very impressive that they were able to get the top speed they got with only a three-speed with a 4.56 axle-ratio. Very impressive indeed. I'd just hate to hear what kind of fuel mileage that would get. It would probably rival a 1970 Challenger with a 426 Hemi in the fuel mileage department (and that is nothing to brag about). If you wanted to do the crate engine approach, you would probably either have to get a manual version or accept that you will only be able to use a three-speed Torque-flite because I read the W5A580 has a torque limit of 427ft-lbs. Unless one of the newer 4-speeds based off of the Torque-flites would work, I think you would be up a creak in terms of fuel economy.