Thinking about getting a ~'85 3/4 ton

scooter70 · June 8, 2004

Lately I've been thinking that I'd like to do a truck once my LS1 '70 Corvette is done and I've had some resting time from the project. Anyone have any comments regarding what I should start with for a truck? I want something with a straight, no rust body and virtually no electronics to mess with. Electronics wise, I will add what's necessary so that I know that it'll be reliable. After putting an LS1 in a 34 year old car, I think that doing a pickup would be pretty easy (and cool).

Which years or models should I look for (or avoid)?

Thanks,

Matt

Colorado Kid · June 8, 2004

Anything from that body style (81-87) would be about the same, except that the rust resistance improved dramatically during that period. Since you're planning to drive it in Michigan you'll probably want to stick to '84 and later for the improved rust protection.

If you want to use the tranny that comes with the truck stick to 3/4 ton or heavier, they'll have TH-400 or M465 which will be up to the output of the 6.0L. I wouldn't trust the TH-700R4 or the Getrag overdrive 4 speed behind a 6.0L. (The TH-700R4 can definately be built to handle the power, but GM didn't build it that way.)

If you hadn't already put an LS1 in a '70 Vette I'd be telling you that parts of this project will get tedious . . . but you're better qualified than me to predict the headaches.

snoman · June 8, 2004

Do not get a 700R4 made between 81 and 83 as they were grenades. 84 thru 86 was much improved over first version and 87 on saw the last improvement of the 700R4. If you get a late model 700R4 they are quite strudy and will live well behind a smallblock if properly cooled. I have 170,000 on a 89 700R4 in a 4x4 burb that I have had since new and the tranny has been 100% trouble free so far and still works like new! Also I would shoot for a 87, just to have the last year they were built like that and also get TBI as well.

Cool Zr2 · June 9, 2004

I'm sure he would use a 4l80-e.

Hecktorx · June 9, 2004

Mid-80s chevys are a great choice. Here's a couple of things to keep in mind when your looking for one. 3/4 tons used an 8-lug 10-bolt in the front and some came with a semi-floating 14-bolt in the back. If you can find a 1-ton, you'll get a Dana 60 front and full floating 14 rear. If you get an 85 3/4 ton or 1 ton, you won't need to run cats.

If I were to get one, I would definately look for for an 87 1-ton. That year would give you all the best parts, including TBI perviously mentioned.

snoman · June 9, 2004

I'm sure he would use a 4l80-e.

I have them both and I much prefer the shifting on my 700R4 over my 4L80E as it is far more predictable and seems to adapt better to different speed and load demands than the 80 does.

Cool Zr2 · June 9, 2004

I'm sure he would use a 4l80-e.

I have them both and I much prefer the shifting on my 700R4 over my 4L80E as it is far more predictable and seems to adapt better to different speed and load demands than the 80 does.

Um..... I don't know about you but nothing is more predictable than a computer.

snoman · June 9, 2004

I'm sure he would use a 4l80-e.

I have them both and I much prefer the shifting on my 700R4 over my 4L80E as it is far more predictable and seems to adapt better to different speed and load demands than the 80 does.

Um..... I don't know about you but nothing is more predictable than a computer.

Or unpredictable becuase of its firmware and programing. My 4L80E is smooth and strong but nowhere near as predicable on shifts as my 700R4 is.

scooter70 · June 9, 2004

If you hadn't already put an LS1 in a '70 Vette I'd be telling you that parts of this project will get tedious . . . but you're better qualified than me to predict the headaches.

It's not really all that tough. It's a matter of interface management. When you make the interfaces as simple as possible, it's not that though. Driveshafts are easy to make, so you can use any tranny to drive the rear end (I'm not sure about the transfer case though. I think that I'd most likely use the one from the 6.0 donor truck). Wiring can be purchased so that you only have to hook up gagues, power, ignition, electric fans, and a fuel pump. Motor mounts are just a matter or making something out of steel. There are lots of little things that get to be a PITA but it's really pretty fun.

Thanks for the tips guys. Maybe I'll start keeping an eye out for an '87 1-ton with a nice body.

The other night I thought about it and was wondering how nice a Suburban would be with the 6.0 ?!??! Maybe a 2wd with a T56 6-speed? That would be cool!!!