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Discussion Starter #1 (Edited)
I currently have a 91 s10, 4.3 tbi 4x4. I recently installed the 2.5” rough country lift kit and put new 31s on it.

If I were to put a 350 v8 into my truck, do you guys think the added lift and tires will cause a decent loss in HP? I want to be able to race it with some buddies on a “legal course”.

Also any mods you think I should consider with the added height and increased horsepower? Steering stabalizer or anything of the sort?

Also, does the factory harness work for the 4.3L TBI to 350 TBI swap or am I going to run lean?

Thank you in advance.
 

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Swap from 4.3 to 5.0/5.7 tho is super simple, the oil pressure sensor wire needs to be extended, the knock sensor wire and coolant temp switch needs to be extended as well. Sanderson makes a very nice set of headers for this swap.
 
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Reactions: Notaperfect10

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Swap from 4.3 TBI to 5.7 TBI just needs a chip from a 91 full size 5.7 4wd pickup or Burb swapped into your ECM. If you take the little plate off the back you'll see that it just pops out. It is a PROM chip. Programmable READ ONLY memory chip. They have a 4 letter code. Unfortunately I don't remember which code that was.
Do a Google search on TBI chips. There may still be folks who have or can burn one for you if you can't find one in a JY. TBI custom fuel injection programming might be able to help.
 
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Reactions: ala_frosty

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The 5.7L swap is pretty easy as swaps go. You should not lose any horsepower by switching from your current motor to a larger motor. Or maybe I didn't understand that portion of the question?

Other things to change for racing: Acquire spindles and brakes from a 1998+ 4x4 blazer and you'll get bolt-in dual-piston front brakes. And if you're throwing money at it, put a proper locker in the rear end (not a G80).

Finally, for on-course racing, you probably want a lighter vehicle, so remove the entire interior except for the driver's seat and convert it to 2WD by replacing the trans with a 2WD unit and losing the xfer case and front axles. That'll save you 200-300 pounds. It'd be a lot less work to just buy a 2WD truck for racing and keep your 4x4 for its intended purpose.
 
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