Mike, first of all, I applaud your effort. If folks didn't ask 'what if', we'd still be riding horses. Go for it. I've thought of the same kinds of things myself.

A few questions/comments.

1- What happens in the tranny when you rotate the pan so it's no longer level? Will there be any issues with fluid pickup etc? Manny is your go-to source for questions about that. The trans rotates around the diff centerline. the new pan just need to maintain the same effective level from the centerline, and volume. It will take a custom pickup.

2- I have a 6.0 in my '07 GMC Serria pickup. It has a 3.70 final drive and it will indeed make a lot of power but it makes it at 4000-6000+ RPM. With a 425 and 3.70 final drive, you're still going to be at 3000 rpm at 60mph and I don't know if that is the sweet spot for LS torque. The ls motor has one of the flattest toque curves out there. it will make all the power you need at any rpm. Hook a trailer to that truck and it will still run down the road in OD.

3- Hal StClair did a masterful job installing a diesel with motor tranny in his Royale. What he did was use the entire tranny and front wheel drive system from a 1 ton 4wd. Not anywhere like a kit that you are thinking about but he has a modern overdrive 5 speed tranny and a final drive that fits the motor. The RWD portion is blocked off at the tranny. The 425 is the major problem with updating the GMC imo. Yes, I have followed Hal's build and he indeed do a masterful job. But it as far from a bolt-in as you can get. I would like a kit where average skills could install. And I agree about the trans, we don not have reasonable trans option. But I believe we have reasonable engine options.

4- What about rotating the MOTOR instead of the tranny? The fuel injection shouldn't care but you'd probably have to modify the oil pickup and still modify the oil pan. I looked at that as I was rotating the engine around to find a balance that I thought would work. That combination required require the motor to be at about a 40 degree angle. I just don't think the average customer would accept that.

5- From a kit standpoint, raising the hatch is much more viable than modifying the step for most folks. I agree whole heartedly. It was Jeff Sirum who pointed the step issue. I was just about to mock it up on the frame he provided to me. The valve cover and intake and hatch are within an inch of each other. I would gladly give the step for hatch. I hope I can fab a bolt in part for the step.

Just a few thoughts from another fabricator. It was great meeting you in Dothan.