LS7 Engine Swap

Well to start off, I'll let everyone know that I am number 31, backorder for the LS7 crate engine. From what I have been told, the crate motors could be out in a month, 3 months or maybe six months. Either way, I need time to get all the info I need for the swap. I do know, and have heard the same so far that, as long as I add all the smog of the Corvette I will be alright. I know somebody here has more info for me on engine swaps. I am putting this motor into a 1996 Chevt Tahoe. Anyone following the project, I'm thinking about an, Allison Transmission, and IRS

I don't know what you are looking to pay for the engine but Fred Beans Chevrolet was advertising them for right at $13,000 minus the dry sump oil system and accessories. I've seen prices up to $17,000.

Depending on your timetable, and if you are willing to spend the money, you might look into the 6L80e transmission that is slated for debut in the next generation of the SUVs and trucks.

Do you think that is better than say, an Allison? I would run the 4L85E, but if I can have a Allison I would go for that. I'm not sure if either will bolt up though?

6L80E should bolt up. It's the next generation of auto transmission and will help keep you in your power curve. The Allison will be a bigger pain in the ass to adapt than the 6L80E since it's designed for the Isuzu diesel engine. I would bet money it's got a totally different bolt pattern on the bell housing than a Gen 3 or Gen 4 engine. Anyone seen an Allison on a gasoline engine?

I guess the main PITA is going to be the controller for the six speed since it will take a whole new PCM to control it. Maybe TCI or someone will create a stand-alone controller for it like they did the 4L60E.

The new generation of transmissions, including the Allison, have thier own control modules separate from the ECM. This is good because the LS7 uses a control module that supports the CAN bus and likely would be able to talk to one of these TCMs just fine.

Allison trans have a circular bolt pattern, and would require a custom flex plate and bellhousing adapter, and they are heavy. the over size converter would eat up all your low end torque.

what is a 6l80e?

I think the 6L80E is the new six speed auto HD. I've been waiting for something different from GM for a while now. They always tease me with new trannies lol!