1991 V3500 Project Heavy Hauler

[Greenlee]

What did you have to do to get the dual tanks working? I've read on here where other people had problems with the dual tanks when doing this type of swap. Something about the tank selector valve not being able to handle the higher pressure. I'm just curious in case I ever get the balls to do something like this to my truck.

[MTCK]

This switch makes it plug and play up to 65 psi.

http://products.pollakaftermarket.co...mids=1805+1821

Hard to overstate how much fun it was to get the super stiff high psi hoses attached with it in place. Double your patience supplement intake the morning you do that.

Swap of the pumps and valve couldnt have been easier in concept. Take out old pumps put in new pumps. Take out old valve put in new valve. Cut crimped soft lines off existing hard lines. Install all new 250 psi pressure and return soft lines with double fuel injection clamps and high tack gasket cement (not really necessary on the return). Supply line is 3/8, return is 7/16. I'd do it again to have 40 gallons of fuel and no transfer pump.

[MTCK]

What did you do for the switch, Willy? Assume you had the higher pressure switching valve?

[Grumpus Monkus]

Outstanding job that you have done with the truck!

[MTCK]

Thanks Grumpus. It's the little details that make the difference- vintage air puts dimples in the back of their dash trim strip with vents so you can install the factory trim level badge on it. Can't say enough good stuff about the vintage air system.

I couldn't find a local shop that could fit the 90 degree hose end in their crimper. Vintage will loan you a crimping tool for nothing but the freight. Great service too. They shipped it the same day I called and asked for options. They will also crimp for free if I wanted to send them the hose.

[MTCK]

Buttoned up and ready for a trip to the exhaust shop tomorrow. Can't wait to finally drive this thing!

To do list won't keep me off the road. Need to install some speakers, wire up the driving, fog and backup lights, wire in the seat heaters and install some mud flaps.

[Greenlee]

Looking good! Your interior has really been transformed from when you first got the truck.

[y5mgisi]

Excellent!

[wildwilly4x4]

I bypassed my valve all together and am running everything from the DS tank. I have my tanks plumbed with a X-over tube on bottom, and a "dual fill" type setup on top. Essentially my two 16 gal tanks act like one big 32 gal tank now. I have no filler door on the driver side.

As for a fix for the switch, I would recommend using a relay for each fuel pump, after the selector switch, thus taking the load off of the selector switch

[MTCK]

Thanks guys and thanks for the tip Willy. I've had no issues since trueing up the grounds. Put about 80 miles on the truck tonight to seat the rings. Wow. The torque is flat awesome. I held 85 mph up about a 3 mile long 7% grade in overdrive without pushing hard at all. It's no race car but it feels super strong. I need to drop the break in oil and go find something to tow. I'll post up a pic of the exhaust shortly. Here it is at the top of the hill. Old 350 would barely hold 55 up this hill bouncing off the rev limiter (floating valves) in second.

[MTCK]

I'm really happy with the tone and volume of the magnaflow cat and muffler combo. 2.5" from the manifolds to a y to 3.5" single out the stock location.

[wildwilly4x4]

Originally Posted by wildwilly4x4

I bypassed my valve all together and am running everything from the DS tank. I have my tanks plumbed with a X-over tube on bottom, and a "dual fill" type setup on top. Essentially my two 16 gal tanks act like one big 32 gal tank now. I have no filler door on the driver side.

As for a fix for the switch, I would recommend using a relay for each fuel pump, after the selector switch, thus taking the load off of the selector switch

That was supposed to say no filler door on Passenger side. both tanks fill on the Driver side

[y5mgisi]

Glad you are happy with it!

[DirtyLarry]

Turned out great Marcus... Nice work! Hope it met your expectations. Wish I lived closer as I would love to hear and drive it.

[MTCK]

Got any pics of that setup, willy? Seems like an option not often used. Can you fill both tanks full bore or have to let it equalize out a bit? Can't be any worse than the rodeo of trying to hit both tanks from one pump...

Thanks Larry. I think it will totally meet my expectations and I'm looking forward to putting a load on it. You never know, you might get a chance to drive it. Wife says she is done sleeping on the ground in a tent so we may have a road trip down to Woodland CA.

I have a few odds and ends to button up. Tiny coolant leak from somewhere, loose wire on the speedo where the wires got a little tight from the AC duct and I need to crimp the last AC hose and get it charged.

One interesting note is you hear about people falling all over themselves paying stupid money for a 1991 NP205 with the VSS, but the howell setup didn't even need it. Do later 4L80E's only have one VSS which necessitates using the t-case sensor for output shaft speed? Mine has two and the only thing I'm using the one in the t-case for is to run my speedo. It is completely independent of the PCM. I got a pin out diagram for my DRAC, hooked up 5 wires to it and kept my stock speedo setup. Switched 12v, ground, two wires to the VSS and speedo output.

[DirtyLarry]

People like to jump through their very own pie hole wasting money on Dakota Digital instrument clusters too anytime someone does a later model engine swap

[Farm Shop]

Great build! Lets see a "finished" engine bay pic!

[rgunlock]

Congratulations Marcus! Glad to hear you are happy with your upgrades.

[Grumpus Monkus]

Congrats! I enjoyed reading the previous pages. All the best.

[MTCK]

Thanks everybody. So far so good. Few punch list things to get done like chase down a little coolant drip. Under hood pic as requested with the last AC hose on.

[68Timber]

Sweet. What size magnaflow did you install?

[MTCK]

Inlet / outlet is 3.5". Not sure on the case length but the part number is 12909.

[carboncrew]

Oh man thats purdy!

[Dieselwrencher]

The exhaust looks really nice but the under hood shot is awesome! Great work!

[DirtyLarry]

The engine bay looks great Marcus! Funny, the Polar Bear has a coolant drip again too. If you recall I played hell getting the Spectra CU774 radiator where 3 of them showed up beat to smithereens. The third one I kept and had a local radiator shop fix it….. twice…..now it needs to go back again before we head out on the trip. Great radiators, they just do piss poor packing for shipping.

Curious to hear what you think of the Magnaflow as I just literally had mine taken off today and replaced with a Spintech. The Magnaflow had a horrible noise at 68 MPH on up. Not a drone, just a weird noise that made the engine sound like it was in 3rd gear or the fan clutch was locked up. Weirdest muffler I’d ever heard. I think the muffler was just too small for the volume of exhaust passing through. So far I like the Spintech but man…..are they pricey. It sounds like a Flowmaster but entirely different with practically zero interior noise. Zero drone like a typical Flowmaster. Sounds good though

New SpinTech with their X-pipe


Magnaflow 12568