4.2 to 5.3 swap

[CoreyH]

Can't believe no one has brought this up here, but just wondering if anyone on here has been successful on a build like this? I am just about to start this project, just about have my engine complete. I know the transmission support bracket needs to be moved, I know that its not a plug and play deal, I know theres going to be some splicing, and I know its going to be fun!
Just curious if anyone has successfully done it yet. Can't seem to find any website where it's been done yet.

2004 Trailblazer LS 4.2 I6
building a 5.3 block, TBSS oil pan, ported and polished 243 heads, LS9 cam, TSP LS1 102mm intake manifold, need a Camero water pump still and fuel rail. The harness is from a 2001 Chevy 1500 5.3, I know there are 3 different sensor connectors that need to be replaced in order for the TB sensors to be installed instead of the truck sensors (want to make sure the PCM reads them correctly)

 

[Mooseman]

There are a few discussions on here:
http://gmtnation.com/forums/threads/4-2-to-5-3-engine-swap-talk.6835/

http://gmtnation.com/forums/threads/4-2-to-5-3-swap.1459/

(4.2 to 6.0, same difference)
http://gmtnation.com/forums/threads/dead-4-2-swap-to-6-0.12516/

 

[CoreyH]

Cool thanks man. I subscribed to the 6.0 swap. Apparently its not finished either but it has some useful information. I have an idea on what needs to be done, just wondering about the wiring. Even then, I already know what connectors are different and need to have new connectors spliced in, just curious to the rest. Will hopefully be starting my swap within the next few weeks. Trying to get it painted right now. Just got the body taped off tonight, should be priming it tomorrow hopefully

 

[l008com]

I have nothing to add on how to do the swap, but I can tell you that you are doing the right thing. Mine is a short wheel base 5.3 and its NICE. It is FAST. The factory 5.3's also had the larger brakes like the SS, which is also nice. It's so fun when merging on the highway and you floor it, the truck takes off. People must be scratching their heads. And the beautiful sound it makes, that sound isn't supposed to come from this truck It's awesome.

This is what the 4.2's sound like compared to the V8s: