4.3l to 5.7l

[99-gmc_ss_clone_5.7]

Just have a couple of questions, im looking to swap my 99 4.3liter to a 5.7l vortec, now because i live in southern ontario my truck needs an etest every 2 years. They plug their bullshit computer into the obd2 on anything 98 and newer and see if all the monitors are ready and there is no engine light on. Now i know they put obd2 into vehicles in 96, i believe, but i was just wondering if i could get a 5.7l vortec from 96-98 and have it work with my 99 computer. If all the sensors and everything will plug into a motor older then 98. Etests are bullshit, i dont know if anyone would be able to help me with that question but its worth a shot, thanks, im also looking at making it a 383 stroker and am unsure if thats even possible with fuel injected motors, 

[GrumpyGhost]

It would be easier to just swap in a 5.3l or 4.8l or a 6.0 then to swap the truck over to a 5.7l. not saying it can't be done, just kinda unessacery and odd unless you're swapping in a Corvette 5.7l. The older 5.7l truck engines used a distributor and don't have some of the sensors that your 4.3l has. Also the 4.3l computer will run a 5.3l or 4.8l or 6.0l with just a simple tune from a tuner and then you don't have to worry about swapping computers and disabling vats. and a few other things that'll cause you issue.

Basically doing any sort of swap and keeping the truck on point to pass emissions, you need to swap in the same generation of engines that fit your truck. I recommend a 5.3l that way you can keep your current transmission without worries of burning it up, a 6.0l will mate to it, but it may not live long even running stock.

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[99-gmc_ss_clone_5.7]

The 4.3l has a distributor, so from what i have been told the 5.7l will drop in no problem, with the same computer, all i have to do is get 2 injector plugs and run them to the computer and reflash it. If i do a 5.3l i believe i would have to change the entire wiring harness, because i dont have any plugs for the coil packs

[GrumpyGhost]

http://harrishighperformance.com/?page_id=27

99 is a tricky year for these trucks, I guess the 4.3l didn't convert over to newer style wiring until 2002, anyhow you are correct, a 5.7 will drop in and the link I provided above should be a good starting point for your wiring, my bad, everybody makes mistakes.

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[carnau]

This is exactly what I did to my 1985 c10. I swapped out a 4.3 to a 1998 5.7. But then again I didn't need half the wiring.