350 V8 Swap! 1991 GMC Sonoma

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The Chevy S-10 and GMC S-15 (later Sonoma) were the first compact pickups to be built by a U.S. manufacturer. They paved the way for the later Colorado/Canyon successors. These small pickups typically had an inline-4 or V6 under the hood, while this low mileage beauty from 1991 has had a Chevy 350 cubic inch V8 sandwiched in. It’s been in storage for a few years but looks to be in great overall condition. Located in Bowling Green, Kentucky, this nifty find is available here on eBay where $7,000 has yet to crack the reserve.

Until 1982, if you wanted a small pickup truck, it likely came from Japan, even if it was sold by a U.S.-brand dealership. Chevy, GMC, and even Isuzu offered their badged version of the little “S” truck (the Isuzu was called Hombre). These were popular trucks, with Chevy selling the majority of the variants built through 2003. The GMC S-15 became the Sonoma in 1991, the year the seller’s pickup was assembled. That was the same year as the one-time GMC Syclone came out, a performance truck that’s considered collectible today.

The big story for this Sonoma, besides its beautiful condition with only 25,000 miles, is that an engine/transmission swap/upgrade has taken place at some point. A 350 crate V8 sits below the hood, with aluminum heads and intake along with a Holley 4-barrel carburetor. It also has electronic ignition, bringing the drivability of the truck into the 21st Century. The seller says the transformation is one of the cleanest jobs he/she has seen in one of these transports. A TH-350 automatic transmission is also along for the ride.

According to AutoCheck, this truck has had only three owners and no reported accidents. The paint is said to be original except for the front bumper and roll pan. The interior is equally nice, and the only flaws may be a noisy roll-down window, a non-working speedometer, and an oddly placed tachometer, all fixable. The bed looks good, and the truck comes with a nice tonneau cover that snaps into place like on the Syclone. The tires have tread but may be flat-spotted from sitting, so the buyer might want to change those out. All sorts of photos and videos have been uploaded by the seller. These include more pics, a walkaround clip, the engine running, and another with the truck in action.

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  1. Tbone

    Somebody’s going to need some Caltracs

    Like 4
  2. Davey Boy


    Like 5
  3. Stan

    Bit of an understatement on the spool Russ. Just my .02. Way rather have a posi-traction here.
    Lovely looking swap, still has a stockish appearance. Blow past a few surprised 😮 drivers in the hwy passing lane. 💨

    Like 7
    • Earl

      It’s a purpose built truck, I am thinking of doing something like this with my ranger.,old school all the way.

      Like 5
  4. DW

    Let’s see….no overdrive….no catalytic converters….a spool in a street truck….no fuel injection….air conditioner needs service….and the reserve is still not met at $8200? I mean it’s a nice looking truck, but to be this high I would expect better.

    Like 10
  5. Gary

    I like this……only bad thing i saw on the pictures is the oil filter jammed up tight against the exhaust pipe…..

    Like 5
    • sakingsbury20

      right on that…..with all the things done right with the install, how could they overlook such an easy fix as a remote oil filter kit…..

      Like 8
  6. Joe Haska

    I agree with all the comments, there are definitely some things that need to be addressed. However I have a friend that has owned several Syclones and I have got to drive them many times. This to me would be the next best thing for a smaller investment. Especially when you’re looking for a nice used truck, they are not cheap or easy to find

    Like 4
  7. PairsNPaintMember

    During my time living in Kansas City, MO I owned an ’84 S-10 with a 350/350 swap. Edelbrock heads, manifold and carb, no-name headers into glass packs. Nowhere near as nice as this one, the conversion was done by a guy who lived in KC, KS. Painted Prowler Purple, it could pass anything but a gas station. A good front end alignment took care of the steering problems it came with. I redid the interior and fixed a few drive-ability problems and sold it for a profit. It was a fun little truck.

    Like 4
  8. C Force

    A friend of mine had a 89 with a 355 sbc and 700r4.They are fun to drive and you can burn the tires off em’.the headers for these are interesting,the driver side is usually a two- piece slip fit because the steering shaft goes between the tubes.

    Like 3
  9. Ron

    Great looking little truck, should be about at all the money…

    Like 2
  10. Steve

    Heavy front and light in the rear, gonna be quite a handle being 2 WD. Syclones and Typhoons were AWD and much more controllable than this one would be.

    Like 1
    • PairsNPaintMember

      Actually, not that bad with aluminum heads and manifold saving weight. You just have to remember it’s not a sports car. I never had any handling problems once I got the front end properly aligned.

      Like 3
  11. David

    I had a 91 s10 with the 4.3 and it was like a 350 with 2cyclinders cut off, a great engine that I never had a problem!

    Like 1
  12. Howard A. Howard AMember

    Naturally, I’m going to tout the accolades of the S-10/S-15 Sonoma, I’ve had several, and all great trucks made right here by the great folks in the USA( Ohio?). The V8 here is pure fluff, and that’s okay, but most would want an economical example of these, as nothing new compares, and as David said, the 4.3 was the best V6, like the Dodge, BECAUSE of its V8 roots, but let’s face it, just not needed today.
    As an owner of both American and import,, I can say, without reservation, there was no need to buy an import, when America offered these. Again, I suppose I’ll take it to my grave as to why imports were so popular, aside from spite, perhaps, as outlined in the Toyota pickup post. Okay, the 2.8 needed extra care, and turned many off, but with that extra care, I got a ton of miles on one. The S-10 Blazer my ex drove, not so much. Don’t get me wrong, V8 is way cool, and a nice job here, but you’ll get sick of spinning the tires at every throttle application. A V8 could be somewhat economical, teens, maybe, but the temptation would be too great to give ‘er heck, and be satisfied with single digits. Winter? Fugetaboutit,,still, a cool truck.

    Like 0
  13. Howie

    Sold $10,700, 32 bids.

    Like 1

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