Thinking GMT400 3500 Dually for Track Day Towing, Thoughts?

[Supercharged111]

You're definitely going to be upgrading your setup if you stick with this long enough.

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So yeah, bigger is better. Duallies tow like a dream, I highly recommend 4 wheels out back.

 

[the_elegant_fox]

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Well, I’m one of y’all now. Truck did not make it 7 miles post purchase and needed a tow. Likely bad gas and a needed carb tune.

Best I can tell, this is a diesel chassis with a 454 swap, cammed and with a hot carb.

 

[the_elegant_fox]

Yeah, I think there’s going to be a slight headache in getting this 454 running right in the 6.5 turbo truck. Browsing a few threads on it, it seems like a less common but not impossible swap. It has been running in a 454 configuration for a long time though, so the swap has to have been done well enough for that. Last sale was in 2019 and I think it had the swap by that point.

This explains the gauges not being hooked in, seems like that’s a wiring spice or two needed.

Folks said it had a new distributor and I wonder if the fuel delivery issue is also an engine timing issue.

 

[Supercharged111]

Has the tank sender been swapped out for one that accepts a charcoal canister and properly vents the tank? That was one aspect I covered in my swap.

 

[the_elegant_fox]

Has the tank sender been swapped out for one that accepts a charcoal canister and properly vents the tank? That was one aspect I covered in my swap.

I haven’t had a chance to diagnose since it’s at the shop but that might be a possibility. Would a poorly vented tank cause sputtering throttle and backfires?

I do know it it can use gas in the regular tank and it has a 2nd tank in the bed that the owner used most of the time. He said it was easier to measure out gas for that bed tank and that’s what he used mostly. In a dual tank setup, there might be some fuel sending issues.

 

[Supercharged111]

Well I know it can create a vacuum in the tank if it's sealed and you pump gas out but don't replace that volume with air. A vacuum in the tank will prevent fuel from being pumped out. Of course a vented cap could also solve this issue and if you're carbed then that's the route I'd take if you're staying carbed. Then again if you're carbed that 2nd line may already be a vent? We need to know more about this setup.

 

[the_elegant_fox]

Ah, I’ll need to check the caps when I see the truck next. From what I remember, the bed tank was a solid metal. Owner said it was off his old hot rod, akin to a moonshiners tank, but a box. I’m kicking myself for not getting more pictures but it really dove right into trouble. Hoping to get more info from the shop come Monday.

 

[the_elegant_fox]

The more I look into the symptoms of a bad or very mistuned carburetor, the more I think that’s the culprit.

 

[Supercharged111]

By the sounds of things there's a lot of stuff to go over. Tank in the bed sounds suspect too.

 

[the_elegant_fox]

By the sounds of things there's a lot of stuff to go over. Tank in the bed sounds suspect too.

Yeah, this is true. I haven’t been around it long enough to figure out if they feed into the engine in the same way or not. What would be the proper way to run a dual tank setup?