Jeep Wrangler I6 to 1990 GMC 4.3...anyone?

kis86

New member
I just was looking into whether this was possible...how do I know what transmission I have? It's a 1999 Wrangler Sport, 4.0 Auto. Has anyone done this and what would I need...an adapter, the engine, mounts, ... :?:

I imagine this is the same engine as the Chevy 4.3, but I'm not positive. The idea came up because my dad drives an '89 GMS Sierra 1500 with that engine, and it gets about 20mpg highway :shock: and had quite a bit of horsepower. He's had the truck for over ten years, towing a work trailer all over the place and it's been a really good one. I love my Jeep, but if I could get a little bit more than 10mpg in town that's be great :lol:
 
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The 4.3L isn't much improvement over the 4.0L engine, would be cheaper and easier to stroke the 4.0L into a 4.7L or larger.

If you go with a 4.3L or SBC, find a complete drivetrain from engine to transfer case, will keep costs lower since you don't need to buy adapters.
 
yeah I bought an 89 s-10 at a junk yard for 500 bucks got the complete drivetrain out of it and put it in my jeep. Then i scrapped the s-10 at a salvage yard at got 225 back. So it was a cheap powertrain swap, but you'll also need the motor mount kit.
 
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