Hi there guys!
Ive got a few questions for ya regarding an engine swap in my 5.3l Buick Rainier AWD. Okay so ive been doing a lot of looking online for an assembled LS engine block. Im leaning more toward an LS2 402 c.i. block from Texas Speed and Performance cause i like the idea of having more cubes and a more modern motor. Now i know that the SS Trailblazers have the ls2 in them starting in 2006 which is pretty much the same body as mine but my concern is that my vehicle is a 2004 gen lll and therefore has the same pcm as the LS1 and gen lll silverados, but the 2006 SS uses a different pcm than i have because its a gen lV. So my main question is, and im sorry if its a dumb one but i just wanna make sure before spending 4 grand on a block, but would my pcm be able to control an LS2 with propper tuning or would i need to buy an LS2 trailblazer pcm and wiring harness? Or would it just be easier to buy a gen lll ls1 and keep my current pcm and wiring harness? Any info you could give me would be greatly appreciated. Thanks in advance!

 

You can buy the adapter harnesses to run the gen IV engine with your gen III harness and pcm. You need the extension harness for the cam sensor and for the knock sensors.

And you'll need a lingenfelter box for the crank signal. But maybe if you call Texas Speed they can build you the motor with a 24x reluctor wheel instead of a 58x, that will save you from having to buy the converter box.

 

okay so they must have relocated the cam and knock sensors on gen IV i take it?, so therefore i need a longer harness? would i also need a different timing chain cover and cam sprocket? and what about knock sensors where did they move them to on the ls2? are they on the block or are they still under the intake but use a different connector?

 

Yea the cam sensor is in the timing cover and you'll need a new cam sprocket and timing cover.

I believe they are in the side of the block now.

If you werent worried about it being aluminum you could do an LQ9/LQ4 based 402. Then you could just drop it in.

 

Cool build. Keep us posted

 

I had an 06 with dod and loved the truck but family outgrew it.
The 04 should be straight forward with using your stock oil pan and pickup. The stock 5.3 in your truck should be cast iron. With the weight difference of an aluminum block you should consider spring change or go with cast iron 402 for handling. Those trucks with the 5.3 can get a little squirlely with the short wheelbase and soft springs in the suspension. If you would remove 75 lbs or so with aluminum 402 it might not handle very predictablely. Just my .02.