6.6 L gas engine into 2008 sierra 1500 4 dr 4x4.

[george trying to help]

I have been searching the forums and finding little on the subject. I have a 4l60e transmission I am going to spend 1200 to get it beefed up. AI, I am hoping a 6.6 bolts up to it. What other issues besides reusing my 4.8 flex plate for 6.6l? I have a list of engines that fit in this model and years for you. But i am wondering about 6.6 knowing it will have to go on the dyno.

Gmc sierra 1500 engine swap compatiability

 

You can also use the L92, L9H, or L94 6.2L. All Produced 403-Hp/417-Tq.
~2007.5-2009 L92-- VVT, Non FlexFuel, Non AFM/DOD
~2009.5-2013 L9H-- VVT, Flex Fuel, Non AFM/DOD (Same as L92, with the addition of Flex Fuel)
~2010.5-2013 L94-- VVT, Flex Fuel, AFM/DOD (Same as L92 and L9H, with the addition of Flex Fuel and AFM/DOD)

~2007-2013 Cadillac Escalade (L9H for MY 2009, L94 for MY 2010-2013)
~2008-2009 Chevrolet Tahoe (as RPO code L92)
~2007-2013 GMC Yukon Denali/Denali XL (L92 for 2007.5-2010, L94 for MY 2010-2013)
~2007-2013 GMC Sierra Denali (L92 for 2007.5-2010, L9H for MY 2010-2013)
~2008-2009 Hummer H2 (as RPO code L92)
~2009-2013 Chevrolet Silverado 1500 (as RPO code L9H)
~2009-2013 GMC Sierra 1500 (as RPO code L9H)

-2500 hd series lmm. Ly6

The 6.2L engines listed, are for the most part drop in.
Any Gen4 5.3L Engine, and the L76 6.0L Truck Engine is plug and play for the most part.
You will need to have the ECU Tuned if going with a larger engine.
Me personally, would remove any AFM/DOD Hardware from the engine you plan on replacing it with, and use a Non AFM/DOD Cam with the same specs, or a small performance upgrade cam.

 

[KARNUT]

You have my head spinning. Over the years I spent very little time doing engine swaps after the 80s. My computer controlled GM trucks or Ford and Ram diesel’s I modified with the stock setup. With the diesels I went over the counter with banks and modified the transmission sometimes with a tune. Very little time, money and work the diesels would run with the performance cars of the day with a turn of a noob. Longevity wasn’t affected because your street driving. Gas vehicles from a tuning or supercharging brought the same results. Very little work not a whole lot of money especially doing it yourself. No guessing results were painless. My current ride. I could bolt on 100HP in one weekend for very little money without affecting longevity on the street. Now you can buy a ford regular cab work truck 2019 and up. Put a 12K Roush kit on it and get over 700 HP. I’ve seen it done. The directions stated above. I see nothing but frustration and guessing. Or am I missing something. 

Edited February 2, 2025 by KARNUT