1986 Chevrolet C20 to Silverado K2500

Hi everyone.
I have a 1986 C20 pickup truck. Manual trans. Crank windows. I love it. It reminds me of my childhood.
It came with a 305/sm465. It was a real dog. I got 9 mpg driving straight highway from CT to NH. It was fun. Not a project.

I bought a junkyard 5.3 thinking I'd never find a 6.0. Paid for the ECU to be unlocked and reprogrammed, specifically for my 2wd 3.42 rear end. It's just an engine swap. Not a project.

Then I decided I couldn't take full advantage of the 5.3 with a sm465. So I found a NV4500.
Just an engine and transmission. Not a project.

Rebuilt the trans.

Then I found a 2000 2500 frame. It was important to me to keep the truck a 3/4 ton. Just a frame swap. Not a project.

Disassemble trans. New main shaft since I was converting to 4wd. Had to get a 4wd tailshaft housing. Reassemble. Not a project.

Then I found a 6.0. The cam bearings were worn down to the copper. So I tossed the junkyard 5.3 in and sent it.

It ended up being a project. The truck took 14 months to finish. I cut the frame and shortened it to get the right wheel base. It's a 5.3/nv4500/261. Essentially a 99-07 Silverado that looks like a Squarebody.

Now I found another 6.0 with harness and ECU. My major issue is my speedo is about 16% off because I had it programmed for 3.42 and now I have 4.10s. I asked for the cheapest solution to reprogram just the speedo and ended up here with an OBDLINK LX in the mail.