Brians1

Need some assistance on the following question please:

I need to replace the fuel sending unit and while im there im going to replace the fuel tank and the various fuel lines, straps, and grommets.

Motor is a 350 now (455 is on engine stand getting finished). I am running the standard manual fuel pump on both motors

When I look at sending units I see 2 options...3/8 inch only or 3/8 inch with 1/4 inch return line

So which one do i need ?

Brian

Brians1

I think I found my answer....searching forum threads

"Yes, I'm looking at the 71 Assembly Manual (which is almost 100% identical to the 72). Section 8, page 104 is the non vented system that was used with the 350 engine cars. "

So my current 350 setup has a single line sending unit, and when I get my 455 installed, I need the dual line sending unit - that accurate ?

Brian

RetroRanger

IDK about the correctness, but istill run my 350 fuel pump w no return w my 455. no vapor lock issues

Brians1

Good to know as I was wondering

Greg Rogers

I kept smelling gas at the rear of my 71 Cutlass, no puddles under car. I thought it was the rubber lines, but after removing tank I found the sender tube was no longer swedged or soldered or whatever causing the gas smell at rear of car. I checked on Rock Auto and found a new sending unit for about $30.00! Cheap! I ordered it and replaced along with all the hoses. I was surprised to find the sender for that cheap. I thought I would have to go to Fusick or similar. Maybe you'll want to check w/ Rock for your sender and maybe even a tank..

Brians1

I'll look at rock auto this AM.

I decided since I will be putting in my 455 in Feb\March, Im going to go ahead and put the sending unit in that also has the 1/4 in return line, I'll plumb it to the engine bay and cap it off, this way I'm ready for the 455 transplant with the fuel pump that has the return line (working with a form member on a used 1/4 return line now vs buying new one). Im going to grab a few feet of 3/8, 5/16, and 1/4 fuel line and some clamps that way way when I swap in the new tank, I'll change those out as well. I still have the original vapor canister as well (have to check its condition).

I took a few pics underneath last night with my phone so I could make sure of my setup, here is a peak..


Thanks
Brian

Brians1

BTW - great call on Rock Auto - WAY cheaper than OPGI for the same tank and sending unit - almost 40% cheaper. Just purchased it
SPECTRA PREMIUM GM34R Fuel Tank $143.79
SPECTRA PREMIUM FG91D Fuel Sending Unit $33.79
Thanks - Brian

mrolds69

I'm looking at that Spectra sender, and I see it's different than the sender they had available before. Did you install that unit, Greg? Does it work normally, like the needle at overfull when full and somewhat accurate? Before the float was different and the pipes at the top weren't bent right. That's what I had heard. Old unit looked like this...