Thinking GMT400 3500 Dually for Track Day Towing, Thoughts?

[the_elegant_fox]

Alright, he didn't try churching it up as a Corvette engine or anything weird?

Nah, not that I can tell. I don't think PO was the swapper, they just threw a carb and MSD distributor at it.

 

[the_elegant_fox]

Got the VIN decoded

 

[Keeper]

rear has 4.10's with a G80.. nice

 

[RichLo]

...

New 750 quadrajet carb

.....

When I was looking at the engine bay picking it up, they carb definitely had Holley embossed on it. It was shiny too, like this one: https://www.holley.com/products/fuel_systems/carburetors/street/parts/0-80508S

Seller doesnt know much then. It may be Holley's spread bore to fit a factory manifold but its not a Q-jet. Dont get me wrong, its not a bad carb, its a lot easier to tune than a real Q-Jet but take that as your first warning sign that you may be digging into something that has unknown history.

You can put a bore-scope down the spark plug holes to see if the pistons have .030 stamped on top of them. If they don't then its a classic 'craigslist rebuild' rattle can paint job on a factory engine.

You can also run engine block numbers to see where it started its life. It could still be a gold mine or it could be a worn out smog engine.

 

[the_elegant_fox]

Seller doesnt know much then. It may be Holley's spread bore to fit a factory manifold but its not a Q-jet. Dont get me wrong, its not a bad carb, its a lot easier to tune than a real Q-Jet but take that as your first warning sign that you may be digging into something that has unknown history.

You can put a bore-scope down the spark plug holes to see if the pistons have .030 stamped on top of them. If they don't then its a classic 'craigslist rebuild' rattle can paint job on a factory engine.

You can also run engine block numbers to see where it started its life. It could still be a gold mine or it could be a worn out smog engine.

Yeah, I'll have to start with block numbers and go from there. This definitely seems like it'll need some legwork from myself to tie a bow on it.

 

[Jimmy D]

I have found when pondering the purchase of a vehicle with engine "issues" and little history, it's safe to assume it needs a new engine and bid accordingly. I also shy away from any vehicles with after market goods under the hood. I prefer all stock under the hood, but that's just my preference. Truly, all used vehicles are a crap shoot and some new ones too! The first new car my dad ever bought he didn't make it home with it.

 

[the_elegant_fox]

I have found when pondering the purchase of a vehicle with engine "issues" and little history, it's safe to assume it needs a new engine and bid accordingly. I also shy away from any vehicles with after market goods under the hood. I prefer all stock under the hood, but that's just my preference. Truly, all used vehicles are a crap shoot and some new ones too! The first new car my dad ever bought he didn't make it home with it.

I have been looking at 6.5T crate engines as a backup since that would be an easier replacement, maybe a better 454 done right. It does come down to the state of the fuel system. I ran the carfax out of curiosity and it's lived it's whole 4 owner life in North and South Carolina so that explains why the body and frame are in good shape.

I didn't make it home either! Haha, had to take the train back.

 

[the_elegant_fox]

Trying to match from memory since I will be seeing the truck next on the coming Monday:

It looks a lot more like the Mark IV 454 in these pictures https://www.autoevolution.com/news/...-golden-age-s-most-impressive-v8s-229887.html

Rather than the Mark V 454 that would've come in the trucks: https://www.motortrend.com/uploads/...?imwidth=150?w=768&width=768&q=75&format=webp

Main thing that makes me think that is there's all these accessories and tubes on the front of the Mark V that I don't remember seeing. It also had a rounded look to the valve covers. What are the key visual differences between the MK IV and MK V?

 

[HotWheelsBurban]

Trying to match from memory since I will be seeing the truck next on the coming Monday:

It looks a lot more like the Mark IV 454 in these pictures https://www.autoevolution.com/news/...-golden-age-s-most-impressive-v8s-229887.html

Rather than the Mark V 454 that would've come in the trucks: https://www.motortrend.com/uploads/...?imwidth=150?w=768&width=768&q=75&format=webp

Main thing that makes me think that is there's all these accessories and tubes on the front of the Mark V that I don't remember seeing. It also had a rounded look to the valve covers. What are the key visual differences between the MK IV and MK V?

The older generation 454 had the stamped steel valve covers on it, like the engine you pictured from this truck. All the 454/7.4 engines I've seen in the 400 trucks from the factory, have the cast aluminum valve covers, usually painted black with the tops of the fins machined off so they're silver. And the later engines have some smog control lines that are absent on the older ones.
So it seems to me, that some previous owner pulled the 6.5 when they couldn't get it fixed, and dropped a random "454" in its place.
With enough time,$$ and dedication this could still be a very capable combination. You'll have to decide if you like the rest of the truck enough to deal with it.....

 

[99xcss4]

The older generation 454 had the stamped steel valve covers on it, like the engine you pictured from this truck. All the 454/7.4 engines I've seen in the 400 trucks from the factory, have the cast aluminum valve covers, usually painted black with the tops of the fins machined off so they're silver. And the later engines have some smog control lines that are absent on the older ones.

this is accurate 88-90 square body and 88-90 gmt400 454 old valve covers 91-95 gmt400 and I think 91 square body 454 being gen v and not mark iv have the valve covers you are talking about I have never seen a gen vi 454 vortec in person but from videos and pictures the valve covers are the same as gen v only no more oil fill and the fined section is also black