Hello I'm a new member, trying to find info about motor swapping.
My question! Is it possible to replace the LS1 In a Hummer H3T with a LT4 (from a Zo6)?

The quick answer is: Yes, it is!

The longer answer is: Yes, it is, depending on how much money and time is available to put into it, and how functional you want it to be when "complete". I can say immediately that it will not drop in, plug in, and start without a lot of other work. On a related note, most folks tend to think "Can X engine fit into Y body and bolt to Z transmission?" . . . and this is fine, but they often forget the little stuff that is much harder to sort out:

- How to get gauges to work
- How to get the PCM (that will need to come with the engine) to talk to the TCM and BCM
- How to get the climate control to work
- How to get the rest of the driveline to put up with the new engine (that is always more powerful than the original)

If you read through all of this, have a bazillion dollars and/or a bazillion hours of time to throw into it, we'd be interested in following this project and helping with advice where possible. The best place to start a thread for this is the "General GM Chat" section.

Welcome aboard!

Thanks for responding "Ccub" and also for the wisdom certainly something to think about and consider, now considering going the turbo route for the LS1 that'* in it and upgrading the trans, xfer case, and downsizing the ring & pinion to 373'* versus the 456'*.

Could be fun!

This definitely sounds more feasible than swapping in a Z06 engine. I've actually seen a bunch of examples of turbocharged LS1 engines.