1986 GMC Sierra Classic - Flatline
 

Hello everyone,

Let me introduce the proud new member of the family my 1986 GMC Sierra Classic, 454, Turbo 400, 32 spline NP205, Dana 60, Corp 14 bolt. blah blah blah...

Below are the photos right before I purchased the vehicle and I have already made a few improvements.

I will get an updated picture when I get home and show some of the new goodies that are going on her shortly.

The truck is dubbed "Flatline" because my wife said its almost dead, and I hope to bring her back to a nice daily driver.

Dave

Re: 1986 GMC Sierra Classic - Flatline
 

I love it. Nice score! Those trucks are hard to find.

Mike

Re: 1986 GMC Sierra Classic - Flatline
 

Attached are some pictures of the truck as it currently sits.

I was able to score four BFG All-terrains in 285/75/16's for $150.00, that is when I decided to sand down the stock wheels and paint them black. The hubcaps are from a friend that has an over abundance of square body parts.

Hopefully, soon I can find the correct GMC covers and run them.

Re: 1986 GMC Sierra Classic - Flatline
 

Attached are the new parts that I have for Flatline. I have a whole new front clip assembly and two more doors. I also scored a new professional products intake for 50 bucks and a set of Jeg's headers for 130 bucks both of which are brand new.

The idea with the truck is to help her breathe a little better, dump the emission garbage, and get the body work moving in the right direction so it doesn't look like swiss cheese. haha

I have ordered almost all of the sheet metal except for the bed, so as time allows I will start tearing into the body work, which I dislike greatly....

Re: 1986 GMC Sierra Classic - Flatline
 

I have been eyeballing that front clip for a while. I guess you beat me to it. :)

Re: 1986 GMC Sierra Classic - Flatline
 

I'm assuming that is NOT a PA truck due to little to no major rust. I am officially jealous, I've been looking for a similar truck for some time and had little luck.

Re: 1986 GMC Sierra Classic - Flatline
 

I got the clip a while back, its sitting outside my house now just waiting. I think I have found a bed, so I can start the tear down process.

Re: 1986 GMC Sierra Classic - Flatline
 

The legit one tons are hard to find and if I do find them they are always DRW. I actually picked up this truck in Mill Hall, PA. The guy that had it was going to steal the NP205 because it is the 32 spline model and stuff it into a variety of Jeeps he had.

Re: 1986 GMC Sierra Classic - Flatline
 

Cool build, as a fellow Pennsylvanian, I'm in!

Re: 1986 GMC Sierra Classic - Flatline
 

I've been looking for a one ton prefer dually, but could be single wheel for quite some time and have only physically looked at one so far, which might not seem bad, but I've been looking for probably 4 years now. Oh well the right one will come along. If not I'll convert a 2wd.

Re: 1986 GMC Sierra Classic - Flatline
 

So I was able to get some work completed on Flatline. Things are pretty busy right now with the children in sports, so it cuts down on any real free time.

I found a spot on the frame that I didn't like so I added a patch panel, before coating the frame with KBS coatings.

Two things: 1. Don't buy any color other than black. 2. This coating really is a quality coating, but my recommendation would be to spray it rather than brush it on. It does lay flat and no brush strokes can be seen, but if you are really particular on your build, spraying it would be the better choice.

Re: 1986 GMC Sierra Classic - Flatline
 

While the frame was drying in between coats, I decided that the emission garbage needed to make a swift exit.

My intentions are to yank both smog pumps, all the various plumbing, the stock manifolds with vent tubes, and finally pull any unnecessary electrical wires. This will allow me to run the new intake, headers, and finally clean up the engine bay.

Re: 1986 GMC Sierra Classic - Flatline
 

Below is the carnage, let me tell you those exhaust manifolds put up a fight. I only broke one bolt and one spark plug. This poor truck hasn't received much love in a long time.

After I finish hanging both new headers, I will finish the exhaust and move onto the intake and various wiring.

The next mod will be the cam while I am in there with new lifters, springs, seals, retainers, timing chain, and a new one piece metal oil pump shaft.

Re: 1986 GMC Sierra Classic - Flatline
 

I saw that you moved it inside. I have been waiting for an update. Are you going to pull the cab so you can finish coating the frame?

Re: 1986 GMC Sierra Classic - Flatline
 

Below are the predicted numbers with my setup after I toss the cam in. The truck is still running the stock peanut ports and will for quite some time. This should help motivate the truck down the road better and hopefully, not destroy any drive train parts. :metal:

Re: 1986 GMC Sierra Classic - Flatline
 

Not at the moment. However, contingent on what rust I find, I may. haha

Re: 1986 GMC Sierra Classic - Flatline
 

I wish I could pull my cab, but it will have to wait till next winter. Mine is just like yours at the moment...all clean and shiny in the back and old and crusty up front.

Re: 1986 GMC Sierra Classic - Flatline
 

I have 3/4 or 1 ton GMC caps for the rear that you can have for the ride if you're interested.
Let me know.
Jon

Re: 1986 GMC Sierra Classic - Flatline
 

I like the truck a lot. I wouldn't be able to resist if I could get one with those colors and keep the exterior stock appearing (with the bigger tires). Funny how the ladies see something almost dead and we see something with so much potential. Flatline is a cooler name than Potential though.

Re: 1986 GMC Sierra Classic - Flatline
 

I like your build....that one of the best paint schemes GM ever put on their trucks ever...my painter has a K5 in that paint scheme......good luck on you build.....

Re: 1986 GMC Sierra Classic - Flatline
 

Yes sir, I enjoy a good road trip. I can PM my info if that works for you?

Re: 1986 GMC Sierra Classic - Flatline
 

I fell in love with the paint scheme when I first saw it. The truck is still on the stock springs, the biggest I want to go at the moment is a 34 or 35" tall tire but I would like to be 13.50 or 14.50 wide. I love these square bodies with wide tires.

The tires that are onmit are just 285/75/16 ATM.

Re: 1986 GMC Sierra Classic - Flatline
 

This is the paint/decal that will be on the bed of the truck whenever I get it painted. The idea ties in with the truck being dead, and coming back to life; thus the flatline then a pulse.

Re: 1986 GMC Sierra Classic - Flatline
 

Those of us fortunate enough to be riddled with emissions crap, vacuum lines, and endless connections of stupid stuff. I think everyone will enjoy the before and after, below.
I have to get some pictures of the installed intake tonight, I may even set the bed on the truck.

Re: 1986 GMC Sierra Classic - Flatline
 

In tearing everything apart, we have made a discovery. Originally, I thought the truck had 157,000 miles on it. After tearing into the internals, it differs from my original thoughts. The truck appears to have only 57,000 original miles on it.

All gaskets are original, the head gaskets are still metal. The distributor and intake valley are stupid clean. The cam looks great from the topside, etc. I guess it's better to be lucky rather than good!

While I'm in here, the truck will be getting a new thermostat, vacuum hoses, and probably radiator hoses. Here's to hearing her fire soon.

Re: 1986 GMC Sierra Classic - Flatline
 

Mans truck 1 ton 454 4 wheel drive love it! Looking forward to more progress.

Re: 1986 GMC Sierra Classic - Flatline
 

Here is the new intake in place with the carb mounted. I need to score a new thermostat housing and we will be one the home stretch.

Re: 1986 GMC Sierra Classic - Flatline
 

I asked two buddies to stop and help put the bed on. It resembles what a truck kinda looks like. It reminds me of a bag of Skittles with all these colors.. haha

Re: 1986 GMC Sierra Classic - Flatline
 

Thanks for the kind words. I will keep plugging away at it.

Re: 1986 GMC Sierra Classic - Flatline
 

Sorry for the long delay in progress on the truck. Life gets in the way with a herd of children.

Anywho, below are some of the most recent updates for good ole Flatline.

This is my first real attempt at bodywork so any input is appreciated. I'm still learning how to pretend I am a body man. I'm happy with the replacement of the floor, cab support, inner and outer rockers. I just need to finish up the cab corner on the passenger side, then onto the drivers side.

Re: 1986 GMC Sierra Classic - Flatline
 

I also picked up a set of new shoes for the old girl.
They are pretty rough, but for 100 bucks its kind of hard to pass on a set of TSL SX's in 36x12.50x16.5 with chrome steel wheels.

I will run the BFG's AT until I lift the truck. I also scored a set of 4" front springs to lift the truck. I'm trying to decide if I want to run a shackle flip on the rear.

Anyone have any insight on the shackle flip? ORD and Di4x seem to make nice kits, but I want to retain the weight carrying capacity of the 1 ton.

Re: 1986 GMC Sierra Classic - Flatline
 

The rockers and floor looks just fine to me. Let me know when you are ready to get rid of those BFG's.

Re: 1986 GMC Sierra Classic - Flatline
 

Looking good. More rust than I initially thought, but for a PA truck not bad at all. Keep up the good work. Any idea on a finished paint scheme and color?

Re: 1986 GMC Sierra Classic - Flatline
 

Sorry for the slow progress updates, the truck hit the back burner for quite a while. However, I have been able to make progress on quite a bit.

1. I made a new rear bumper.

2. I finished the passenger cab corner and hung both the inner and outer fender on the passenger side.

3. Lastly, I am in process on the drivers side and almost ready to weld on the outer rocker panel. The inner needs a bit more fitment.

My questions for the group are, what paint brand have you used, and what type of undercoating do you feel works well, and what have you used for heat and sound insulation in the cab?

Re: 1986 GMC Sierra Classic - Flatline
 

I haven't gotten into paint and undercoating yet, but am pretty sure I am going to use Raptor liner as my undercoat on the bottom of the cab and bed floor at least. For sound deadening I went with the Home Depot route and am really happy with the results... at a fraction of the price of Dynomat or other type products.

Re: 1986 GMC Sierra Classic - Flatline
 

Great work!!!

Re: 1986 GMC Sierra Classic - Flatline
 

Glad to see you're still making progress. You did a great job on that rear bumper.

Re: 1986 GMC Sierra Classic - Flatline
 

So, I have been a super slacker at posting, but I have been getting some work accomplished.

1. The bed is bolted down.
2. All body work has been welded in.
3. Filler and primer are covering any welds, I will do final prep before paint.
4. I seam sealed all the inside panels and floor panels of my welds.
5. I got the front clip back on it.
6. My gift card purchased grill has been installed.
7. The exhaust is now complete. 3" collectors to 2.5" duals.
8. The rear bumper is mounted and bolted down.
9. New plug wires, cap, and rotor are installed. (plugs were good)

Re: 1986 GMC Sierra Classic - Flatline
 

More pics

Re: 1986 GMC Sierra Classic - Flatline
 

Next on the agenda is to:

1. Under coat the cab and bed.
2. Replace seals in the hydroboost.
3. Send the carb to Cliff Ruggles to be rebuilt.
4. Insulate the cab with sound deadner.
5. Finish my license plate light with LED's.
6. LED upgrade for the dash lights.

The last pic is the support crew, they are the heart and soul of the operation.

Let me know your thoughts guys!