Positrac conversion 85 GMC 1500 LWB
 

I inherited this one from my grandfather. Basicly a farm truck with a few dents and very little rust. Now its a 2.73 ,10 bolt and I want to upgrade the rear end so it won't get stuck on wet asphalt. Also looking for opinions on crate motors. Nothing wild just a good thumping cam to scare off the ricers in my old truck.
Any advice would be great to save time and money.

Without posting a budget you have in mind I could only suggest

Summitracing.com

They have pretty much everything from a factory replacement to all out race duty parts including crate engines - Gm Performance as well. Their tech people are really good with their direct product knowledge.

Summit also has Ring and pinion gear change kits.

Another route would be to swap out the rear end in the truck for a wrecker replacement - the truck is a popular vintage so you could opt for another gear ratio with posi if you wanted without killing the bank and its a fairly simple change out. If you go this route just make sure the axle tubes are STRAIGHT on the replacement. Some of the 1500's had softer tubes that would bend if the truck was overloaded - taking out the bearings and ultimately the rear end.

If your going to buy a new posi buy a " Eaton clutch type posi" most others are JUNK. I build rear ends as part of my business and have seen stock motors tear up th factory G-80 option gov locks, the true tracs and especially the Auburns. Keep in mind your truck has 28 spline axles too so only the stuff built for 87 and older will be correct, Smitty

If you aren't going to change the rear-end gears than you could just swap in a mini-spool for the time being.

http://www.summitracing.com/parts/RMG-78-1028-1/

i would check the local junk yards many chevys came stock with posi easy swap the whole rearend

Smitty,

Whats your opinion on Richmond gears "powertrax" for offroad use?

I am looking at adding it to my 95 Tahoe 4X that runs about 350hp. Also just put it in a 92 Samurai that I am starting to build.

Thanks

We bought a couple different versions of them years ago and when they engaged and disengaged when under hard power it sounded like a rifle going off under the vehicle fwiw. If you were on a strict budget and not running much power it wouldn't hurt to try, remember, all the load is completely loaded onto the cross pin when running them though so it will only be as strong as the weak factory casing, Smitty