Motor swap questions/ brainstorming

Discussion in 'The Engine Bay' started by jd350az, Dec 12, 2016.

  1. jd350az

    jd350az Newbie Premium Member

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    Planning on doing an 8.1 swap the beginning of the year. My 1989 suburban blew a head gasket and in looking around to rebuild it or get a rebuilt motor I realized a swap isn't that much more and I have always thought the TBI 5.7 was sluggish for a 3/4 ton burb lifted on 35's. I've also needed to regear the diffs, I think they are 3.73 and I want to go to 4.10 or 4.56. The next problem is it took a lot of RPMs to go highway speeds with the 3.73s and if I go with lower gears I will want an OD even more so I was thinking 4l60 or 80.

    How does the 8.1 compare to the 6.0? Weight, power, etc. Does the 6.0 bolt up into older Chevys? I haven't researched it much, everything i saw said might as well go 8.1 for the power and not much worse mpg than the 6l. It's mostly a cruiser, hunting, easy trails with family, camping, etc. It is my tow rig, but i don't tow regularly and nothing i have or have friends that have requires more than a half ton. But someday maybe? Lol. The way i drive and use it i would benefit from low end torque more than high end hp. What about costs of the 6.0 vs 8.1 swaps? I'd stick mostly stock reliability over power as well.

    I was also looking into swapping out the th 400 to get an overdrive. I was looking into the 4l80 since it's usually the trans behind the 8.1(or is it the 85?). If I buy a built trans like monster is there any benefit of the 80/85 over the 60/65 or even 700r4? I assume it's simpler to get the ecm/harness set up for the 80 since it was stock, but I imagine the 700 could be setup relatively easy as well and how different is the 60 series? I'm a few months from getting started and buying anything but I'm just wondering what to look for. The 700 is a lot cheaper and a 4l80 almost twice as much and double the core charge as well. Still hoping I can find a whole donor vehicle but they are pricey as hell in AZ, all trucks command a premium here, would pay less to buy online and get it shipped out here lol.

    Thanks for your time!

    -JD
     
  2. skunked

    skunked in the garage Premium Member GMOTM Winner

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  3. jd350az

    jd350az Newbie Premium Member

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    Thanks, I have read them all. Larry's polar bear was the first thing I found on Google when I searched for suburban motor swaps. He started this whole thing in my head lol. I've read Kay's as well on Pirate. That's kinda what I figured with the trans.
     

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