'89 Vortec V6 into '85 Jimmy 4X4

[m_oakes]

I have an '85 GMC Jimmy 4X4 with a dead 2.8L 2BBL in it backed up to a 700R4 (so I'm told). I want to put an '89 Astro van Vortec V6 (4.3L) into it.
Obviously I need all the control modules, but how difficult is it to match the two wiring harnesses?
I am assuming the Vortec will bolt right in, as with the rest of the Chevys.

[87 STEPPER]

m_oakes,

Welcome to the board

The first thing i can tell you is your trany isn't a 700r4.

The 2.8L engine doesn't have the same bolt pattern as the 700r4

The next thing is the engine mounts are not the same so you will need to get a set for the 4.3l

I think the easyest thing for you to do is to find another jimmy or blazer in the junk yard that has the 4.3/700r4 combo and get everything from it for your truck the wireing harness is the correct set up and will have the right plugs. Where as the astro is totally differant and will require alot of modifications in order to make it work.

You will also have to get the exhaust sys. and maybe the trany cross member mount and driveshaft and that will all be the right stuff if you get it from a truck like yours you may also need the radiator the 2.8l one may not be big enough for the 4.3's cooling requirement's.

I think that's about it but if i forgot anything im shure someone else will fill ya in

Good luck

[J-Spec C10]

im pretty sure the engine crossmember has to be swaped for the 4.3 too