ChevyFarm

And one more thing -- if you choose a 4L80E you'll need much more gear, because you'll be 2.66 in overdrive with the 4L80E. Waaaay too high a gear even in a highway cruiser. The converter will never couple, or even come close to coupling. And I don't think you built 550 hp to be a highway cruiser.

4 years ago I built a '70 El Camino (don't worry, I also have a '71 M/C SS454) with a 9:1 454, mildly warmed up. Lots of fun. Originally stuck a 200 in it with the 3:31 rear end to see if I liked the gear split with the 200R4 ratios. It worked good -- for about a hundred miles. Then the trans grenaded. Now going to do a 4L80E with a 3000 stall, and switch the gears to 4:30. Using a U.S. Shift controller, and paddles if I want to. Not done yet, but it can't help but work better. Won't blow up, and that's what counts. Should just jump off the line.