'94 c3500 Farm Truck w/ Frankenstein 454 - Project Thread

[the_elegant_fox]

I have a thought, I wonder if the PO left the diesel pump in the tank and since it's higher pressure, it's masking a rich carb situation when really it's just a fire-hose of too much fuel? I'm unsure how the fuel system works with an auxiliary tank in the bed. It was off one of their wrecked hot rods, akin to a shiner tank. It may be jerry rigged to run on just the bed tank and have it's own pump.

Assuming hacky work, could a gas truck run with a diesel pump enough that the PO could use it around the farm? Even if it does have a swapped pump, the old gas/low gas, and carb tune still need to be looked at. It will idle and run, but backfires, cuts out under load, and eventually floods and turns off. Only floods under load though.

The truck has the auxiliary tank sitting right above the pump location, so this area is cut like this post here. Either way, it'll make accessing this area a cinch.

Truck got transported to the new shop today and has a slot for next week, so I'll know more details then.

 

[the_elegant_fox]

Talked with some of my buddies and they mentioned that if it was still running on a diesel pump, we'd see massive excess black smoke and that doesn't seem to be the case here.

 

[Erik the Awful]

It depends on how much pressure the diesel pump makes and how you have the fuel to the carb set up. If the diesel pump is just a lift pump and produces around the same pressure as the gas pump, then it would run just fine. If it's way more pressure, but you have a return-style fuel setup with a 7psi regulator, it'll run fine.

 

[Drunkcanuk]

Just came across this on Reddit, thanks for whoever it was from here that posted the link.

That's one awesome truck. Minus the issues it has. My dream rig is a black one, slammed with a wing like that on a cab extender that removes the rear window.

Keep us updated on your journey.

 

[Sean Buick 76]

The first step would be checking the fuel pressure under load. As Erik said you will need a fuel return back to the tank. The next would be using a known to be good carb. I suggest using these guys, each carb is specked for your combo:

Everyday Performance Rebuilt Quadrajet Carburetor Store ~ Quadrajet Carburetors for Sale

Everyday Performance reconditions and sells classic Rochester Quadrajet muscle car carburetors.

www.everyday-performance.com

Or

Quadrajet Power, Your One Stop Quadrajet Shop

Quadrajet service, parts, kits, restored originals

quadrajetpower.com

 

[the_elegant_fox]

Just heard back from the shop on the truck. It's got issues, but it’s not unsolvable. Looking at a fan shroud, water pump, exhaust leak, oil leak, and valve adjustment. Not gonna be too much in parts, but a decent amount of labour. The carb is in good shape and it's actually like a $1k carb that the owner has on his street truck. Brand still unknown, didn’t go over it on the phone.

It runs, but I think the valve issue is what's gumming up the fuel delivery.

I’ll send the parts list once they get it over here on Monday. I’ll need to add valve adjustments to my skill set. Learning about solid vs hydraulic lifters as well.

 

[Cadillacmak]

It runs, but I think the valve issue is what's gumming up the fuel delivery.

Does that carb have a fuel pressure regulator before it? Most tank fuel pumps are way to much pressure for a carb.

 

[the_elegant_fox]

Does that carb have a fuel pressure regulator before it? Most tank fuel pumps are way to much pressure for a carb.

I’ll have to check, it probably needs adjustment if it does. Once I get the details on the exact make and model of it, that would be a simple search.

 

[the_elegant_fox]

Got the work order in on the truck. Looking at valve covers, gaskets, sparks, water pump, fan shroud, battery, alternator, general tune up and valve adjustment.

Turns out our carb is an AED racing carb in the 850 range, but it's been really beat on https://www.aedperformance.com/competition-carbs/pro-street/aed-850-ho-modified-detail.html


We're going to try to build it with it on there but the backup plan is a Holley 850

 

[the_elegant_fox]

Talking with the shop about the truck, the starter gear bit the dust so we're gonna get a Power Master gear reduction one to replace it.

Looking at a billet kit serpentine system as a potential long term goal along with an EFI Sniper type setup for reliability.

The billet kit is like $2k, and I think that won't be something for this year, but eventually. There’s no accessory belt on it at the moment.

It seems like this block is a 70s 454, but we don't know if it's early or late. The ports will tell, but we haven't gotten that far yet. I'm learning the difference between the generations and I'm leaning Gen IV/Rat Motor, but it could be a 70s motor home 454 that's been rattle canned orange.