hi. I'm Adrian in Kentucky. I'm new to the whole forum thing. I have a 98 gmc jimmy slt and a 99 chevy blazer lt. both are rwd, 4dr, and 4.3 vortecs. the jimmy has been sitting for bout 2 and a half years. the motor locked up on me. I always said I would do a LS swap if the motor ever went out.. I know have to opportunity to do so, but I don't know what I need. I know I need to replace to motor mounts but that's about it. I've been told that I would have to strengthen up the gears in the rear end. any other info would be greatly appriciated

 

Check out "Project Sleeper Blazer". Same forum.

 

Thanx

 

There is a lot that goes into these swaps because of all of the electronics. It also depends what route you want to go and how much modification you want to perform. Are you building this for a weekender or a daily driver?

You can use just engine mounts and headers designed for the swap, but if you use the normal LS truck oil pan you will have to cut a notch in the frame. The same applies if you want to run the A/C compressor in the lower passenger location, it also requires the frame to be notched.

The route i went is to run Current Performance poly engine mounts, headers, a hummer H3 oil pan and a Kwik performance high mount A/C compressor. This way i did not have to modify my frame at all and i have plenty of clearance. (Current Performance sell this as a kit for around 500 for painted headers or 600 for ceramic coated headers)


You will also have to either take the S10 factory harness and the 5.3 harness and combine them to make an integrated harness which is very time consuming and can have some major headaches if anything is pinned wrong or pay someone to build you a harness. Mine was built by Current Performance but it cost me about $800 (well worth it in my opinion because its very high quality and everything including all gauges work perfectly).


For the accessories up front, you can run the factory truck accessories and move the factory 4.3 radiator into the core support, or buy an aftermarket setup. Many people run dodge intrepid electric fans on these swaps.

Im running Corvette accessories because they are shorter than the truck accessories by about 2 inches to give me more room between the engine and fans along with an aftermarket radiator condenser and fan setup. I can sit in traffic here in Texas with 100+ temps and i never go over 210 degrees with my A/C on.

Then you will have to have the PCM tuned to remove VATS at the very least. But i would recommend having a good company tune it for your setup because these LS engines really wake up with just some added timing, Air fuel ratio, power enrichment and torque management tuning.


As far as the rear differential is concerned, Im running my factory 8.5in 10 bolt with a Detroit Trutrac installed in it until i break it. On my 82 s10 i had years ago i was drag racing with the factory 7.5in 10 bolt with a 80s camaro posi unit in it but i only ran drag radials for fear of braking the diff with slicks.

 

@chuckntruck

thanks for that detailed description. that answered all the questions I had. I'm new to this but I know its somethin that I want to do. my mechanic and I have been talkin bout if for a while now. I finally got a good lead on a 5.3 with lowish miles, all accessories, wire harness, and pcm for an affordable price. it will take a lil bit to get it all done because ill be doin it a lil bit at a time. but I will be sure to post pics along the way. thanks again