Not an EXPO type truck but still an engine swap inspiration

[Larry]

Not by any means an Overlander or even weekend exploration rig but thought I would share my latest fuel injected engine swap project with you all. Took a 1993 C1500 Sportside with a 4.3L V6 and stuffed a TBI 7.4L big block in it. Funny little project for my father in law. This is also what has been distracting me from working on the Polar Bear Suburban and Surf Turtle 4Runner for the past few weekends. Now that the engine is in FIL is taking it to the paint shop next then treating it to a set of 18” Coys wheels.

Below are the highlights… (believe me, there was a lot of head beating against the wall along the way)

4.3L on its way out.

4.3L next to the 7.4L.

4.3L mounts just before removing them

Isn’t this nice, engine mount nuts inside the boxed frame so the lower control arms must be removed in order to replace engine mounts. Real bad deal if you have a GMT400 4x4 as the torsion bars would need to be removed as well.

What a hassle just to replace engine mounts

Ready for an engine

Taking a ride to the exhaust shop

Duals + Flowmaster sans cat

Called a friend that owns an AC Delco repair center (instrumentation exchange center) and got hooked up with a new Tach instrument cluster. Even calibrated to the correct mileage to boot.

Old non-Tach cluster

New Tach cluster

Youtube test drive.

Got a few small things to dial in before it goes into the paint shop. The A/C line needs to be reworked in order to connect to the accumulator. Tried to use a 1996-2000 accumulator but those hosers at GM changed the threads from SAE to 27MM in 1996 so no easy way other than cut the hose free at the farrell at the compressor and run a new hose to the accumulator with new crimp clamps.

 

[BigTex]

As usual, awesome work Larry. If the other air cleaner was on there, there'd be a lot of folks that would think that truck left the factory that way. I'd drive it like that for few weeks to mess with the local tuner types! That is the ultimate sleeper.

 

[Larry]

As usual, awesome work Larry. If the other air cleaner was on there, there'd be a lot of folks that would think that truck left the factory that way. I'd drive it like that for few weeks to mess with the local tuner types! That is the ultimate sleeper.

Thanks BigTex. That is my theme when I do these swaps to make them look box stock as much as possible. I had to use the K&N air intake as there wasn’t a factory GM air intake for TBI that works with the later model accessory drive setup with the high mount H6 A/C compressor. Almost looks stock. Tehehehe

 

[toyota_jon]

excellent job, and sounds great!

 

[Balzer]

Gotta love a 2wd short bed big block truck! Nice work! What trans is that? I thought all 88-94 5 speeds had that stupid throwout bearing/ internal slave cyl thing. An external slave is SOO much better but I have never seen that style before.

 

[Larry]

Gotta love a 2wd short bed big block truck! Nice work! What trans is that? I thought all 88-94 5 speeds had that stupid throwout bearing/ internal slave cyl thing. An external slave is SOO much better but I have never seen that style before.

Nah, the integrated slave/release bearing debacle started in 1996. The trans is in this truck is the stock full aluminum light duty NV3500 which it is a crap shoot too see which will be the fuse the drivetrain now….the NV3500 or the weakling 10 bolt rear axle. I built this for my 70 year old father in law so I am not too worried about the trans or rear axle until the wife and I inherit this truck many years down the road. My in laws are great people so I hope we don’t inherit anything for many many years.

My test driving will probably be the worst thing that happens to this truck for a long time. Still have some fine tuning to do yet. She runs well but could be much better. I wouldn’t say it is a fast little truck but it is quick. She needs a bump in fuel pressure to match up to the ECM tune and we’ll see how she does then. An LS engine would have been a much better match for a 2wd street queen but I didn’t have one of those laying around. Big blocks…..I got a few.

 

[Balzer]

Ah my 91 had that stupid throwout bearing thing. But it had the ??getrag?? german or french excuse for a trans. It basically puked its guts into the bellhousing one day and I eneded up swapping in a SM465 4 speed I ended up having to use a 1987 bellhousing, slave cyl, and hose with external slave and a 88-92 SM465 shift housing on the top of the SM465. It was a brutally slow swap due to lack of info at the time.
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From what I can tell the NV3500 is a much better trans than the first 5 speedsbut none of the smaller 5 speeds like to be downshifted to slow you down. The way the gears are cut basically puts a lot of stress on both the back sides of the gears and the bearings.
Anyway im rambling.... Cool swap and you did a VERY clean install I like how you trimmed the fan shroud rather than swap in a V8 version.

 

[Larry]

Cool swap and you did a VERY clean install I like how you trimmed the fan shroud rather than swap in a V8 version.

Thanks! I used a V8 fan shroud and not the original V6 shroud. Used a 1996 Tahoe 5.7L shroud to be exact. I couldn’t find a decent 7.4L shroud and the 4.3L shroud was too narrow for the new radiator plus it is log as a 55 gal barrel cut in half.

 

[Hawkz]

You make that look easy. I'd love to do something like that to my '61 Suburban. Way more power than the 305V6 and probably better mpg...

 

[Larry]

You make that look easy. I'd love to do something like that to my '61 Suburban. Way more power than the 305V6 and probably better mpg...

Hehe, selective picture posting makes it look easy. Believe me, there was a lot of cussing and tools flying around that created sparks bouncing off the concrete floor. This was the most challenging engine swap I’ve ever done. Not the getting it running part, but the getting it stuffed in there part. Doing a millennium 8.1L into a 70’s truck was a cake walk. Doing a major engine swap on a 88 -98 GMT400 truck is a huge frustrating ordeal. I don’t think I would EVER do another GMT400 truck again. I can’t imagine later model 99-06 GMT900 trucks are any easier to play powertrain swaperoo. Glad the physical work is over.

A '61 Suburban would be pretty easy but I wouldn't mess with a 305 V6. Those are great engines! High torque V engine with the fuel economy of a V8. It's all about nostalgia with those. :costumed-smiley-007

 

[chilliwak]

I really like the swap on that awesome:Wow1:rig Larry! A true example of great craftsmanship, and may I say patience in regards to the motor mounts. I did a V6 to V8 swap on an 80s Chevy van once. That also required a huge amount of patience! Funny how that V6 almost looks bigger that the big block when viewed from the front. Thanks for sharing the build with us Larry, and keep smokin those wheels!