Ozz1967

iTrader: (4)

Hey guys,

The 350 I installed in my 84 T/A doesn't have a mechanical fuel pump option on it, the hole was never drilled for the pump rod. I've gone through two holley electric pumps in the past 7 months. Holley says that since I am pulling fuel up and through my sending unit (top of the tank) and down to the pump, that the pump is having to work too hard to pull the fuel, even though the pump is mounted below the tank, thus burning it up. I don't want to drop yet another $150 on something that will only last 3.5-5 months on me.

So I was thinking, what if I installed a pickup from a 85 or 86 model that has the electric in-tank TBI pump on it? I'd use my regulator to pull the pressure down with the return line of course. How hard would it be to wire this pump to my existing relay (the one I installed for my current externally mounted Holley electric pump)?

I'm going to post this in the general section as well. I've got two months to get this thing ready for being a daily driver for the next 4 years, so I need to get this figured out. (easiest thing to do would have been to have the shop machine the damn hole for the mechanical pump while I has the block in the shop being put together...grrr Hindsight really is 20/20)

Thanks in advance!

89redliningRS

That should work fine. I would suggest putting in a walbro replacement pump since you'll have the tank out. That's what I'm running, and when I switched over to carb I'm pulling about 8psi with the mallory 3 port regulator. I think it's alittle high on my setup because of a return line restriction somewhere.

1ADan

iTrader: (4)

the fuel injected sending units wont fit the early carbed tanks - they've got different opening sizes. but the F/I tanks are much more common, so you should be able to find someone willing to swap (or buy one new).

otherwise, the tbi pump will work well with a return style pressure regulator. I ran that setup on my carbed setup without issue

Ozz1967

iTrader: (4)

Ok, so you're saying I'll need to actualy replace my whole tank in addition to the fuel pump?

I need a new tank and sending unit/pump by Friday then, this is the last weekend I"ll have to work on it before I go on vacation. I'll have maybe one more before I ship it to England when I get back from my Trip in the middle of January.

Where can I get one of these famed "walboro" pumps and a good tank? I know AZ can get me a sending unit/pump and tank in 2 days because it's on their website though I'd prefer to help our sponsors before the local chains if at all possible.

1ADan

iTrader: (4)

the later carbed models didnt have this issue, as they came with intake pumps similar to the fuel injected models. However, since yours is an 84, I believe yours is going to be different. Wouldn't hurt to get a second opinion though; I'm kinda fuzzy on some of the early carb model differences.

Ozz1967

iTrader: (4)

Mine is an early 84, no in-tank pump, only came with the mechanical as I have no factory fuel pump relay that I can find. Also, no fuse in the fuse box spot for it...unless it was removed before I got the car. guess I won't know till I remove the tank, though I don't know if I can take the chance.

five7kid

iTrader: (14)

Not true. I've got a TPI pick-up in my '82 tank.

In-tank pumps were used by the factory in every thirdgen model year; crossfire, L69, TBI, TPI, etc.

1ADan

iTrader: (4)

i stand corrected then, my apologies. if its not the sending unit opening, what is the difference on the 82-84 carb tanks that varies from the the FI units? there's definitely enough of a difference somewhere that everyone out there making tanks has 2 separate skus.

definitely don't want to be pushing wrong info myself if i'm incorrect

also, keep in mind i'm referring to the carb sending units that did not have the helper pump

Ozz1967

iTrader: (4)

So the sending unit should work just finr?
I already ordered the tank and sending unit. If it fits, I may return only the new tank, or keep it because its new and clean, depending on how much I have to mutilate the top of the tank getting the old sending unit off. How do I cap the unused line that I won't need? I will have feed, return and vent lines that I will use.

five7kid

iTrader: (14)

It's the internal baffling. I haven't had a problem so far.

1ADan

iTrader: (4)

gotcha, that was the only other thing i could think would be different. again, my apologies for spreading wrong info. noting for future clarification

five7kid

iTrader: (14)

Carb and EFI have the same number of lines. They are all built into the pickup/sending unit. The EFI has high pressure hose fitting on the supply line, while the carb has all slip-on clamped lines. I picked up a repair line from Advance Auto that had the threaded fitting on a hose, crimped to a length of steel line. I bent the line to follow the original routing, then flared the end of the steel part for a fitting at the filter. This was for an LS1 install, but you could do the same thing for a 3rd gen EFI filter (which I used for the other LS1 install with a 4th gen plastic tank - but that's a different story...).

five7kid

iTrader: (14)

A merge of the two methods I used would work for you as well. This is the 4th gen tank set-up with return after the 3rd gen EFI filter. I bought a repair fitting set for the filter inlet & outlet.




I cut/bent the longer one for the supply, bent to fit the location, flared and used a union to the filter inlet. The outlet is the short repair fitting, cut to length and flared. Just use a union instead of the "T" I used.




You can reuse the carb return line from your reg.

Ozz1967

iTrader: (4)

My thoughts were to simply get some high-pressure rubber hose line and a clamp. I guess that won't work real well for this? Reason being is I don't have any tools for cutting/bending or flaring tubing. I was just going to connect inline to my current feed line going to the regulator out of the "feed" line from the pump. I suppose I could get a TBI pump that only runs 17PSI or so...would that work?

five7kid

iTrader: (14)

Well, I was fabricating a high pressure system, so I guess I got carried away. With a return-style regulator, the highest pressure will be the regulated pressure (unlike a dead-head regulator), so, you're right, hose & clamp would be fine.

The TBI pump doesn't have as much capacity at carb pressure as a TPI or similar pump, so just use a good pump.

Ozz1967

iTrader: (4)

I am glad I don't have to re-do my tubing...that would have been the last straw. I have heard alot about this walboro replacement pump. Do you know of a good link to it?

Ozz1967

iTrader: (4)

And you had no problems running your carbed car with the TPI pickup/pump installed? This is the route i'm going to have to go because I don't trust my inline pump more than 3 months.

five7kid

iTrader: (14)

I got the pump from Summit. http://www.summitracing.com/parts/VPN-GCA758-2/

I didn't run this on a carb setup, I did this with the LS1 swap. But, many members have run the Walbro/return reg on carb setups.

Ozz1967

iTrader: (4)

Cool. Hopefully I'll be another!