Picked up a 1970 GMC C3500 dump truck that needs some TLC

[Grumpy Old Man]

I picked up a manual choke kit for 10 bucks as the auto parts store. Was a snap to install and wow, what a difference to have a working choke!

I pulled the plugs and they are pretty fouled again after only about 75 miles, which was one trip to the dump and then just hauling chips around on my land.

I found this on a local craigslist ad:

It has the performer RPM intake which is not really ideal for me, but I can probably sell it and the brand new Mallory distributor, towards a more suited intake and carb. The block is a 020 casting 350 and the heads are 062 vortec heads with roller rockers. Also has high rise valve covers. Cam is supposedly mild. It is a 355, which I guess is the 350 bored 030 over. He had it listed for $800 obo or gun trade. I have offered him a few hundred bucks and a shotgun. Let's see if that works for him. He bought it as it sits for a project he is no longer doing, so it has to go. If I do get it, I'll do headers, pipes and glasspacks.

Stock with a 292 would be nice ,but why put it back the way it came stock ? It couldn't possibly work that way !

 

[murphy1244]

Peter, Your forgetting what the truck is used for. Unless your dump is a quarter mile.

 

[deerefan]

I picked up a manual choke kit for 10 bucks as the auto parts store. Was a snap to install and wow, what a difference to have a working choke!

I pulled the plugs and they are pretty fouled again after only about 75 miles, which was one trip to the dump and then just hauling chips around on my land.

I found this on a local craigslist ad:

It has the performer RPM intake which is not really ideal for me, but I can probably sell it and the brand new Mallory distributor, towards a more suited intake and carb. The block is a 020 casting 350 and the heads are 062 vortec heads with roller rockers. Also has high rise valve covers. Cam is supposedly mild. It is a 355, which I guess is the 350 bored 030 over. He had it listed for $800 obo or gun trade. I have offered him a few hundred bucks and a shotgun. Let's see if that works for him. He bought it as it sits for a project he is no longer doing, so it has to go. If I do get it, I'll do headers, pipes and glasspacks.

Make sure and get the cam specs. You may end up with a motor suited more for performance than grunt.

 

[pclausen]

Yeah, guy doesn't really want to trade with what I have and I yeah, my dump is not 1/4 mile and that engine is probably not well suited. LOL!

I found another 350 pulled from a 74 truck. It's complete except for the carb. It has the factory 4 barrel intake on it. He'll take $275. I'll stop by to check it out Saturday.

Dropping in another small block is the easiest swap I would think since everything will move right over. I can probably sell the 305 for close to what I'm paying for the 350, if I do pick it up.

 

[crazyal]

Not sure what's around you but I have a couple of junk yards that specialize in trucks. When I was looking for an engine for my IH the guy had several that he knew were very good. I ended up with a great running engine out of a street sweeper. Most people pass on truck engines because they are designed for low end grunt. I have to believe there must be plenty of yards around full of GM trucks.

 

[pclausen]

I do have some local junk yards, but they are typically asking $400 - $500 for complete engines. I'll probably swing by there and take look at what they have and see how they compare to the craigs list one for $275. I'll bring my small block chevy parts interchange manual with me to see what blocks/years they all are.

 

[pclausen]

I think I might have made an even better score than the $1200 I paid for the dump truck! I found 69 GMC 1500 one owner, all original, number matching with a 350 4 bolt, 4 barrel carb, with just 34k miles on it (or so I was told...) It had been sitting behind a shed for the last 29 years! It is a manual 3 speed (3 on the tree).

Here's the tag showing it was last on the road in 1984!

The original owner passed away some time ago, and his surviving wife wanted to get rid of it, and sold it to the kid next door who already had a bunch of chevy trucks in his yard. He just got a job and didn't have time to mess with yet another truck, so he put it up for sale, which I how I found it. I looked it over and offered him 500 bucks for it, and he accepted! All he had in it was a replacement hood (I have the original also) and he took out the radiator for one of his other trucks. Other than that, it is 100% complete and original from what I can tell.

So here she is in all her glory.

The truck has the full gauge cluster option and you can also see the low mileage in this shot.

These might even be the original tires from 69 on the front!

VIN number:

Glove box plate:

Close up of second column showing what I think is 350 and V8. It is very hard to make out.

And here is the engine itself. It turns over freely, as does the throttle and choke plates on the carb. Someone put too tall an air filter in it at one point, and I'm not sure why the water pump pulley has 2 grooves on it.

Even came with the original hub caps.

And here's the original title from 1969.

It is almost a shame to rip out the engine from this all numbers matching '69 truck to put in the dump truck...

From wikipedia on the 350. I think this is the engine in this truck. I'll check the casting numbers tomorrow to validate what I got.

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The 350 first appeared as a high-performance 295 hp L-48 option for the 1967 Chevrolet Camaro. One year later it was made available in the Chevrolet Nova, and finally in 1969 the rest of the Chevrolet line could be ordered with a 350. The engine was also exported to Australia where it appeared in many Holden vehicles beginning with the 1969 Holden Monaro. Many variants followed:

L-48 Years: 1967–1980

The L-48 is the original 350 cu in (5.7 L), solely available for 1967 in the Super Sport version of Camaro SS 350 (1967-up) or Chevy II/Nova in '68-79. In '69 it was used in almost all car lines; Camaros, Impalas, El Caminos, Chevelles & Novas. 1969 L-48's use a Hyd Cam, 4bbl Quadrajet carburetor, cast pistons, 4-bolt main casting number 010 Blocks & casting number 041 or 186 heads. Power output was 300HP and 380 lb·ft (520 N·m) torque. Compression ratio was 10.25:1. The compression ratio of the L48 was lowered to 8.5:1 in 1971.
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I suspect I have one of these casting:

Years---Casting--CID-HP->HP-CAPs-Comments
1969-79 3956618 350 165 350 4 car, truck, vette
1969-79 3970010 350 185 370 2 or 4 car, truck, Vette

 

[CompactTractorFan]

Might as well keep the truck, at the rate you are going, you will have your own junk yard soon. :laughing:

 

[wroughtn_harv]

I had a 70 one ton with a mild 350 in it that was a ton of fun and great welding rig. 4:88 rear gear so it would climb out of its skin when I nailed it, happened often, headers, comp cam, intake, edelbrock carb. It was almost as much fun as the 72 3/4 ton with a similar set up, different rear, and singles, even big singles are easier to smoke than duals.

One of my buds bought a clean 70 half ton and turned it into a show truck. According to him he robbed the front suspension from a late model and ended up with all the late model niceties. If I remember right it was a straight swap.

 

[pclausen]

Got the casting numbers and it looks like everything is indeed original:

3932386 Block 68-70 300/350hp
3932454 Heads 68-69 307/350 1.72/1.50 76cc 300hp heads
3927184 Intake 69 300/350hp truck, vette

Another engine pic after removing the air filter and fan.

Valve cover removed. Looks fairly decent.

This truck is way more rusted out than my '70. I think I'll haul it off to the scrap yard after taking the bench seat and instrument cluster out of it. Will also keep the alternator and side mirrors.