How much work and how many headaches would it be to pull a 4.3L V6 and 5spd manual trans from one 98 Sierra and swap it into a 2wd 1998 Sierra with a factory V8/auto? I've done my own repairs all my life on a variety of cars, truck, vans, but never anything like this. Is it possible without, say, custom welding and parts? Anyone here carried out such a swap?

Or more simply perhaps, swap out the transmission, an auto for 5spd manual?

  • I'll just throw it out there ... anything is possible. The better question would be why? 1st gen SBCs are plentiful for cheap (I've got one in my garage I'd sell you :o) If the engine is the problem. The same goes for the transmission, assuming it's a 4L60e. Really, for the headache of hanging pedals for the manual and cutting a hole in the floor, to me it doesn't make sense. Although, if you do have a donor truck, getting this done does make it a whole bunch easier ... especially since they are the same year. I guess it's 6 of one, half dozen of the other. Oct 13, 2016 at 23:58
  • wtb: old body style, v6, 5spd manual, 3rd door, 2wd, not black, not red, prefer white, prefer 1500. I'm currently putting my time and dollars into keeping a new body style with those specs on the road, I'd rather put it into a body style I like. Buy two 98's swap the drive and or power. Then again my city ain't vehicle friendly.
    – Franky
    Oct 14, 2016 at 0:05
  • I don't remember, was the 98 the crossover year between the SBC and LM7 engines? I know 99 had the LM7 engines in them. I used to sell them. Oct 14, 2016 at 0:11
  • That's greek to me. My old '90 old body style truck had a 4.3/5spd, and my current '99 new body style has a 4.3L/5spd
    – Franky
    Oct 14, 2016 at 0:12
  • SBC = 1st generation Small Block Chevy; LM7 = 326ci 3rd generation Small Block Chevy (LS1 variant). Both are V8s. I'm pretty sure the 98 had the SBC in it and the 99 was the first year for the LM7. The LM7 was an iron block engine, as well as most of the Vortec engines used in the trucks (L33 was a different breed). The LS1 and most of the other LS variants used in cars were aluminum blocks. The '99 new body style had a different V6 in it than was in the '90. Hope that helps your understanding. Oct 14, 2016 at 0:17


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