Interchangability 2003 LQ4 with 2006 4L80E ???
I'm building a Chevy Monza with an LQ4 and a 4L80E trans. This is strictly a race car and there will be a large turbo involved.

I haven't seen much in my research that explains the changes in the 4L80e through the years. Before I throw money around, I want to be sure that the 2006 4L80E from an Express van will work with a 2003 6.0 LQ4 from a Denali wiring harness and ECM.
How about torque converters? I plan on running 3000-6500 RPM on the salt flats. This won't be a hard-launching setup as there is no traction on the salt for that. What differences are there between the TC's in 4.8, 5.3, 5.7, 6.0? I'm interested in less spinning mass.
As far as the heads that came on the 2003 Denali- are they 317 or 243's?
thanks in advance!!!
I believe the Denali LQ4 was mated to a 4L60E in the 1500 series Yukon.
Post a picture of the back side of the wire harness trans connector (where the wires come out) and I can tell you for certain what it is wired for.
If it is 4L60E the changeover to 4L80E on the connector is pretty easy. You will however need to add an ISS connector and wires. I have a connector/wire/PCM pin setup if needed.
The 2006 trans will function just fine with your 2003 controller.
The heads on the LQ4 should be the 317's.

