Hi there. My name is Zach Martin from Kitchener/Waterloo, OntarioCanada. First off, I’d like to welcome you to V8 S Series. Together we hope to assemble a database of useful information and friendly members to assist each other in swaps, modifications, and anything s-series related.
Here I would like to share the build process of my 1991 GMC Sonoma. It is a regular cab short box, which was imported to Canada from Georgia sometime around 2001. Being from the United States and never having been winter driven, this truck is absolutely spotless of any rot or rust which is very rare to find in Ontario. We use plenty of salt on our roads during the winter months. Unfortunately, this quickly destroys any hopes of having anything nice if winter driven.
I first purchased the truck in March of 2012. Upon further inspection, it seems that sometime between when it was imported and when the previous owner had purchased it, the owner at the time had completed the truck’s first of multiple frame-off rebuilds. During this rebuild, the owner badged the truck as a Chevy s10 with SS badges. The title said GMC Sonoma, but they are identical trucks in blood. Here are a few pictures of the truck when I purchased it.
As purchased, the truck was a 4.3L V6 TBI engine with a T5 5speed manual transmission. It was equipped with a throttle body spacer, K&N air filter and simple flowmaster muffler on 2.5” single exhaust. The truck had some get up and go for what it was. I was very happy with my purchase.
I have now owned a total of 13 S Series trucks in the last 5 years, which of course means I have developed my own collection of parts and a taste to go along. I immediately changed the front grille to a chrome GMC version. I prefer the GMC due to the billet-style centre section. I also changed the bumper to a chrome version.
HINT: This is a factory bumper with the holes for an impact strip. A friend of mine had used a strip of chrome trim to cover the holes, which produces less of an eye sore and an affordable modification.
Now, funny story. Being an American truck, the speedometer is in MPH. The odometer read approximately 220,000. Being from Canada, I hadn’t even realized that it meant the truck had over 350,000km on the motor. What does this mean, you may ask? Well, within a week the truck had enough of the abuse I give my vehicles. I first heard a simple knock, but didn’t care. That night, I went drifting with an ex-girlfriend. I was sideways at the top of 2nd gear, when I must have over-revved it. I heard a sudden “BANG” and the truck stumbled. I immediately knew what had happened, and pulled over only to find my exhaust was leaking oil and coolant… think about that for a minute.
A good friend of mine, Craig, came to the rescue as we used a tow strap to pull the truck to his place. Once I had my ducks in a row at home, my Stepdad let me use the shop in the backyard to fix the truck. Within 2 hours, we had the front clip off of the truck and the drivetrain out. As mentioned, I’ve owned a couple of these…
The next day, I got the V6 on an engine stand and pulled it apart. I knew I had done good, but this is a little more extreme than I had expected.
I’m not sure what happened in what order, but what ended up happening involved the #4 cylinder Intake valve smashing the piston, the piston exploding into multiple pieces, the wrist pin shearing off of the piston, bending the connecting rod, and then proceeded to pretend to be the Kool-Aid Man and force it’s way through the cylinder wall on the next revolution or eight. Obviously, the V6 was toast and is now probably part of a stairway or some other steel object irrelevant after being melted.
Now, I’m a huge fan of the term “Do it right the first time”, which contradicts itself further in this post but hey… A project is a project, am I right? I take pride in my work, and decided to go ALMOST all out on the rebuild. I started accumulating performance parts and swap parts to install a Gen 1 Chevy 350 smallblock in the truck.
I received a 2bolt block from a friend, and sent it to Twin City Auto Parts in Kitchener, Ontario. Don is the go-to guy for rebuilds in the area. I purchased dish pistons on connecting rods for a good price, or else I would have gone flat top. He also had a crank for the same price as machining the crank I had. I spent around $1200 for him to bore and hone the block to 4.030, install new cam bearings, and assemble the bottom end with the parts I purchased from him. In the end, wasn’t a bad price for a fresh motor. I also picked up a pair of 74cc heads which had been looked over for $200. I now wish I went with something better, but keep in mind this was my daily driver.
Being a flashy truck already, I decided to go with the “Clean and Simple” take on things in the engine bay. I used Duplicolour products to paint the engine “Cast Iron” which is basically just grey. I felt it would turn out good with chrome and black accents.
As mentioned, I like to do things right the first time. This meant cleaning up the entire engine bay while I had it apart. Here is the truck after I pulled the driveline.
I started by using the tools I had available, which consisted of a wire wheel cup on an angle grinder. I spent some time cleaning up the frame rails, which was actually quite easy. It involved clearing bed liner, not rust, which I was grateful for.
I filled some minor holes in the firewall, including the hole for the wiper spray nozzles. I later relocated the line to under the clutch reservoir for cleanliness. I ended up almost completely stripping the frame and firewall to assure everything got a fresh coat of paint. Here is a mid-progress photo with the frame coated in rubberized rockerguard and the firewall in filler primer.
After plenty of hard work, the firewall got a fresh coat of Duplicolour’s Semi-Gloss Black Engine Enamel. I love the finish this provides, and highly recommend the product to everybody. It is a perfect mix between matte and gloss.
As you’ll notice in the next picture, I also cleaned and painted all of the front suspension to match. Here is the motor in it’s final resting place.
A carburetor setup is very simple to wire. Here is a picture of my factory s10 engine bay wiring harness with the vitals tagged and the rest snipped. I did this with no research, simply kept what I know I’d need. I hope this helps a few of you running a carb setup. The purple wire is for the starter solenoid to crank it over.
I did some more wiring and such, and got to this point. I went with an MSD 6AL-2 ignition box, mostly for the 2-step rev limiter and powerful ignition. It also works great with the Pro-Billet distributor I used for firewall clearance caution. You can also see my fuel regulator on the inner fender.
I added a push button on the headlight panel to control my line lock solenoid. I also installed my Momo stearing with with a Grant adapter. The truck had aftermarket carpet installed during the original build, which fits great and is super clean! Once I ran the truck for it’s break in period, we buttoned everything up with the front clip and all other small details not worth mentioning. I apologize for leaving out some swap details, but this is already much longer than anticipated!
After a test drive down my road with open headers, I was instantly in love with this truck all over again. It made the maiden voyage to Autopsy Custom and Repair in Waterloo, ON to receive full 2.5” Stainless exhaust with Flowmaster Delta 50’s and spun magnaflow catalytic converters to avoid the $2000 fine for running without. Here is a vague picture of how things were run. The driver side pipe crosses over just after the tailstock.
Having the truck back up and running was an amazing feeling. A friend of mine Dave Levitt of Dave Levitt Photography held a group photo shoot in Cambridge, Ontario. I was excited to attend to get some great shots of the truck. On the way to the shoot, I washed my truck. Unfortunately, where I had mounted the MSD ignition box was directly under a drain hole for the hood seam which I hadn’t noticed. Water had worked it’s way into the box and caused it to short circuit. The truck died on me a few blocks later, and wouldn’t start. After getting honked at and flipped off, the truck finally fired back up and I limped it to the location of the shoot which was only a few blocks away. We got some great photos! Here are some behind the scene shots during the shoot.
The day came to an end and I had to tow the truck home due to ignition issues. I had it towed to a friend’s place, where he confirmed the MSD was causing the problems. I installed a regular HEI distributor temporarily, while Marken Performance gladly replaced the box for me under warranty. I didn’t have any issues after the new box was installed. Here are a few photos from Dave’s camera during the shoot. I am very happy with these, and continue to use them to this day.
Here are the rest of the photos I collected during the summer of 2012, which was when the truck was in its prime. Having good rear tires wasn’t a common thing.
Being such a small truck, you would think it wouldn’t tow very good. Well, you’re wrong. I moved various vehicles with this light single-axle flat trailer. It rode amazing, even though the trailer axle is solid mounted. The blazer pictured travelled a total of around 200km with no issues. I even passed a Honda Civic during the trip, which is worth a story all on it’s own!
Summer 2012 was coming to an end, the speeding tickets were accumulating, and I simply couldn’t afford to drive the truck every day. With winter coming closer, I picked up a 91 S10 ext cab for a winter driver. My daily driver changed multiple times since, so I will leave that out. As you’ll notice in this next picture, the role changed and my new daily towed the truck to my shop at the time.
As you can see, our landlord was pretty cool. He lifted my Datsun 620 onto the mezzanine to save some space and store it while I worked on the Sonoma. It turned into an entertainment centre, then was later sold due to lack of funds and motivation.
Long story short, I’m irresponsible behind the wheel and decided to pull it apart and rebuild it again to avoid losing my license (which didn’t work, by the way). I am going to be vague here, but stay tuned to the site and you’ll see more!