What are your goals?? If your goal is cheap as possible why not just do a marks adapter in front of the H42? Works great and then you’re just doing an engine swap.
Depending on the tire size and gearing, I would prefer a NV4500 with a V8. It has a deeper 5th gear and you can make the V8 pull it, or not. I Think you can get a split case behind it, or something else.
as implied above the parts list is going to depend on what you’re starting with and your desired outcome. Do you have a stock drivetrain? If so the transmission swap is adding cost. A 5.3 pushes my 4500# 35” tired forty with ease. I’ve done 85 mph but the desirable sweet spot is 60-65mph. At that speed the car fine is just humming along. 1:1 top gear and stock 4.11 gears. Splitcase is likely a bit quieter, but the drone of the m/t’s nearly drowns it out.
When I had a sbc, I wanted the nv4500. The mouse motor was screaming, the ls don’t care. It’ll rev up with a blip of the throttle no problem. What I have is a deep 1st for crawling and 3 gears for street driving(sm465). The spread on those 3 street gear is clunky. If I had the one more gear in that spread between 3rd and 4th (1:1) I think that’d be the holy grail for my purposes. Id probably use overdrive if I had it, but I don’t miss it.
In terms of the engine swap- you need an engine, harness and ecu. What you need after that?
Motor mounts. Like I said, I used to have an SBC so I was able to use adapters from the SBC motor mounts. If you have a stock F style engine you’ll need all new adapter mounts. AA sells them or you can make them.
Cooling fan- I was already using the Taurus electric fan so I kept doing that other people swear by a mechanical fan seems to breakdown to personal choice.
Fuel pump frame mounted pumps are easier to replace. In tank pumps last longer and are quieter. I’m very happy with my Chevy Tahoe pump in the stock tank.
Exhaust manifold/headers. I’m using center dump headers with a custom exhaust. I’ve also read that you can use 2 driver side manifolds. The problem is your transfer case and narrow frame won’t allow you to run the exhaust inside the rails on the passenger side. This takes a little bit of a head scratching, but it’s not rocket science.
An adapter, you’re either adapting the engine to your current transmission or you’re gonna adapt your transmission to your transfer case
If you’re on a tight budget, it’s not terrible to modify the stock Harness. It’s definitely faster to buy an aftermarket one. Additionally, your ECU will need to be flashed.
The gas pedal depending on the year of your LS you can use either the stock Chevy drive-by wire pedal or a stock Toyota drive-by cable pedal.
That’s the shortlist. You can go as deep as you want in this project. Mine is a down and dirty style swap – I found a good deal on an engine and did all work myself. If you’re gonna do it on the cheap you’re gonna need a good Welder I don’t regret the swap one bit. I love it.
