Urban Suburban 1989 GMC Build

#1
I have been a long time lurker here on the form and read a lot of the articles and posts. I thought I would start sharing what I have been working on for my Family hauler. We use this for adventures for camping and modifications are light but focus on functionality and reliability (and Hauling all our gear) Not a heavy off-road rig although it may move more into that as kids get older (currently 2 and 5). That said it is 4 wheel drive but not full on rock crawler.
So for the story. Got this off eBay for $500 about half hour from my house. Actually I was the only bid as it did not run and had a blown trans. It is a 1989 GMC V1500 RV chassis originally built by Grand Prix conversions in MN. The interior was trashed and not salvageable. Luckily with the cash for clunkers there are so many full size suburban’s of this vintage in salvage yards in So Cal I have no problem getting seat frames or whatever else I need. Towed it home then started the tear down to turn it into a drivable project.
[/URL][/IMG]

So I wish I had taken more pictures of trans but it was in pieces inside literally. Luckily I had a friend who owns a trans shop and I took it to him. I told him “build it like it was yours” so it is fully upgraded with HD planetary, corvette servo, shift kit and all the bells and whistles you can throw at a 700R4. Did not cost me anything except buying the parts. Oh and I had to R&R the trans.
Replaced the fuel pump and put new tires and wheels and we had a driver.

[/URL][/IMG]

more to come.
 
#3
So long story short but apparently the old radiator was plugged and not cooling. Went for a short drive and got stuck on the freeway in traffic and the motor got HOT. So hot lost both head gaskets even with pulling over and waiting for it to cool down. So motor was pulled and rebuilt by myself. Basically stock with the exception of speed pro hypereutectic pistons, Edelbrock intake and a slight port and polish on the heads and I had the lower end balanced. I would have loved to do more but I live in So Cal and there is not a lot you can do to this vintage of truck and pass smog check.

[/URL][/IMG]

[/URL][/IMG]

the the new motor of course I upgraded the cooling system. I used a BeCool radiator for a manual trans (no cooler) and made my own fan shroud with dual fans. I use a Ron Francis wiring kit for the fans and temp switch for dual fans along with AC request.

[/URL][/IMG]

With new motor I upgraded my coolers and put some new Hella horns on. Used 6 AN line and fittings for the coolers Larger cooler is the trans cooler, smaller is engine oil cooler. I made some holes in Rad support to get airflow through them and moved them away from front of radiator for more flow.

[/URL][/IMG]
 
#4
Looks good! I really starting to like those old 'burbans! Saw one on Counting Cars last week (or was it this week) that was bought by the count for like $2700... It was a good looking truck, and appeard to have only minimal damage. MY wife thinks I'm nuts, but they're growing on me.
 

clandr1

Adventurer
#5
You are my hero. Great to see someone taking care of another old square body. They aren't quiet, nor powerful, but they just plain get the job done (as long as you take care of them).
 
#8
So after the motor build I took it to an exhaust shop and get a full exhaust system put on (exhaust manifolds back). I started with a Flowmaster but it was too loud and so I moved to a regular RV style muffler. Actually l liked the flowmaster from outside the truck but a highway speed there was a resonance that was deafening. I did a 3” single exhaust after the CAT so it still flows good even with a big ol muffler on it.
Pic of exhaust going on at muffler shop. Tires are Yokohama Geolanders in 32”x11.5” 15 inch rims. In this pic you can also see installed the air bags on the axle. i have a small trailer that i pull somtimes and also I really loaded the back when we went camping for 1st time.
[/URL][/IMG]
 
#9
I actually drove it in this condition for about 20K as a daily driver. The thing I love about this truck is that it gets the same MPG as a new one. I get about 15 to 17 MPG on hwy. My brother in law has a 2010 Denali that gets the exact same MPG. And I joke with him that my truck cost less than one of his payments! You can do a lot to a rig if you think about it from that prospective. Why buy new when you can recycle old into a more useful vehicle.

[/URL][/IMG]
 
#11
The coolers I used were Derale series 10000 stack plate coolers. I just measured the space I had and ordered the closest size I could. I welded uprights to the rad support to bolt them on and then plumbed the lines. The engine cooler goes to the stock location above the oil filter. For the Trans I used hard line adapters and they are not very long until they hit the hard lines. All fittings etc are Summit Racing AN hose ends and line.
 
Last edited:
#12
One of the things that is on going even now is the modifications to the interior. I am using a combination of Hushmat and Dynomat (left over from another project) to insulate the interior. On the roof I believe it is foil backed insulation from soft seal although I did not have a box for it. It has foil on each side and is about ½ inch thick.

[/URL][/IMG]

[/URL][/IMG]

[/URL][/IMG]
 
#14
There is a more cost effective material that works nearly as well as Dynamat. It's the simple foil backed window flashing sold by Home Depot or Lowes. It's a rubber sheet with adhesive. Works fantastically well. I think it's called Peel and Seal. They have larger sizes for covering larger areas.
 
Last edited:
#15
Woofwagon i had some boxes and the Hushmat is pretty inexpensive (compared to Dynamat at least!) Yes it made a huge difference in sound quality with just playing the radio in the shop. the truck feel very solid now in back instead of tinny. Luckily total investment on this was under $200.
 
Top