Ohiols1

I'm a noob on these engines, but learning and researching quickly. Was hoping someone could help recommend a great setup for an H1 Hummer engine/trans/tcase swap. The H1's are heavy, so torque will be important, not just horsepower. I want to go gas, not diesel. I've been looking at the LT engines. Could an LT4 be used? Or is it just not designed for torque specs needed for a truck? I imagine putting the LT4 supercharged bolted to 4x4 truck transmission and tcase. Love what I see for LT Supercharged engines out there. This would be for a daily driver, so it would be great to have good performance, but I'd really like the modern, comfort and quiet like my Ford pickup. Not 100% on the top of the list but decent gas mileage wouldn't be bad too. Again, would love my H1 project to be my daily driver.

FFDP

iTrader: (2)

I'd advise against the LT engines with how complex they are with direct injection and how hard it is to tune the computers if running a factory controller. So much stuff needs to talk with each other and nothing can be off, otherwise the engine will not function correctly.

The earlier engines like the LSA are more friendly to use if you wanted a factory supercharged engine. I'd also suggest an aftermarket engine management system like a Holley.

Of you could use a LQ4 or LQ9 mated to a 4L80e on a stock computer, then add a TVS blower to give you an extra 100 horsepower and torque. Would be an easy 400/400+ at the crank doing something like that. Tuning is the biggest thing.

No matter what you do, it's only going to get 10-15mpg in my eyes at the most. The H1 is heavy, uses really large tires with lots of rolling resistance, so there is a ton working against you.

strutaeng

Those earlier H1 vehicles had the earlier NA 6.2 Diesel and the 6.5TD, right? I'm assuming yours is an earlier model? Does yours have the TH400 or the 4L80E? I would imagine either would work. I don't know what transfer case it has, but I would say keep your transmission and T-case.

Engine options I would say there are a few. How heavy are those beasts anyways? Like 8,000 lb curb weight?

Maybe the largest displacement NA LS you can build yourself for the torque? Those 6.6 Gen 5(LT) gas engines are starting to be very appealing for swaps now (I believe you can convert them to port injection and delete the direct injection with an aftermarket intake). Or you could do a 6.6 stock crank into like an aftermarket LS cast iron block. Or any larger displacement for that matter.

I don't really know much about force induction other than it's awesome!

Ohiols1

Here's some rough factory specs of an H1. They aren't very powerful by today's standards. Many swap this out with a more modern duramax/allison setup. I'd love to see what the more modern gas engines can do. Haven't eliminated the duramax completely, but just wanted a quiet engine if possible and it's less complex of an install than a duramax.

Diesel: 6.5TD, 170HP, 290 lb ft
Some models had Gas: 5.7L Gas, 190HP, 300 lb ft
curb weight about 7000+ lbs

4l80e transmission
242 tcase

FFDP

iTrader: (2)

If it's already got a 4L80e, I'd swap in a 6.0 with a blower on a Holley system that can control the transmission too. With a good fuel system it should have no problems making over 400hp on the engine alone.

If you built up the 6.0, it would make more power of course or if you went with larger cubic inches.

strutaeng

Agree with @FFDP

Those original HP numbers for the 5.7 SBC and 6.5TD are kinda comical by today's standards if you really think about it; but hey, that's what they had back then and I don't think those vehicles went really fast during their service life and use. At least they didn't use an even-more-pathetic SBC 5.0 LOL.

The other questions are gearing and tires. I bet you have numerically high gears? Like in the 5.something? Tire size? Are you going to do any highway driving? The 0.75:1.0 4th gear on your transmission will help vs direct 1:1 if you had the TH400.

I would be interested to see a build thread whichever way you go on the engine ☺️
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Ohiols1

we’ll see, I’d love to do a build thread too.

Ohiols1

So help me with the numbers. I know I’d want torque over horsepower for something like a heavy truck, but if I wanted to build a Hummer up with kind of a novelty build and put a LT4 would I run into problems? The LT4 hp and torque numbers look really impressive even compared to the L86 and L8T. Surely the LT4 would have the power wouldn’t it? But let me know, I’m ignorant with this all so I’m open to any wisdom you can pass on.

FFDP

iTrader: (2)

Yes, it would have the power but it also cost probably way more than the amount of a old school 6.0. Plus 6.0 replacement parts are way way cheaper.

I see used LT4's on ebay for $17,000. A used 6.0 is maybe $500-1000, toss a couple parts at it, a blower and you are at maybe $7000-7500 all in if you bought a new one. Plus you need to factor in the other stuff needed for the LT4 with the fuel system and yadda yadda. Yes the 6.0 needs a good pump as well but a simple 450lph with a regulator is all you need.

rang-a-stang

My vote is an L18 8.1L. Thats what I am doing in my truck too. They make 400 ft pounds at 2500 RPM and over 5000 from about 3000RPM to redline if you tune them correctly. You can control them with any Gen 3 LS controller, and they are not too hard to find. It will bolt to a 4L80E.