Late Gas Tank Early Car

Eric_Shea · Eric_Shea's Garage

Hi Gang,

Has anyone ever put one of the late model gas tanks in an early car? I'd like the extra capacity.

I have a 71 RS Clone (T based). The new tank is out of a 1987 car. I have both tanks here now and I noticed a fairly large difference in the connections.

My current connections are a banjo fitting for the return and the screened outlet both with female screw fittings on the tank. Both are toward the center of the tank.

The new tank has a simple press-on clamp style outlet (I'm guessing due to the size) and a screw on (male this time) return.

I'm guessing the outlet on the new tank won't be a problem. Is there a fitting for the return line that I can put in-line?

Any advise from anyone who's BTDT is greatly appreciated.

Thanks!

E.

cnielsen · 03-17-2005, 12:04 PM

I've done it a couple of times. You may have to play with the fittings a little but all in all it is pretty easy. The old sending unit seems to not be calibrated correctly for the late tanks as there you will be able to go much longer once the light comes on.

Good upgrade though...go for it!

jpnovak · 03-17-2005, 12:20 PM

I did it too. 78 tank in 71 tub. Bolts in.

Search and you will find...

Fuel tank return fittings

Eric_Shea · Eric_Shea's Garage

Thanks,

That post seems to have the info I need. I'm printing it and will review it tonight.

Thanks again,

Eric

911pcars · 03-17-2005, 01:02 PM

I have a late tank in my '69.

The chart on the link has a lot of fittings. I remember attaching a hose and a plug on the return line (unused) with hose clamps. I remember attaching a hose to the fuel pump (carbs) with hose clamps.

I don't recall anything special was needed. Mechanically, the tank bolts right in. One drawback; the larger tank reduces the access space to install an Optima-sized battery in the passenger side battery box - my old one anyway. The new model Optima, a little smaller in one dimension, may fit but haven't verified.

Sherwood

topic-related pic..... really
old vs new

Eric_Shea · Eric_Shea's Garage

Why would there be no need for the return line? Even with a carbed car? Mine has carbs today but I'm building the 3.0 MFI engine for it.

911pcars · 03-17-2005, 05:04 PM

There was much discussion about this in another thread. First of all, factory carbed engines didn't use a return line (at least in '69).

When converting to carbs (from CIS), the factory return lines are often used in the now lower fuel pressure ciricuit, but it's entirely optional. Some say the constant fuel recirculation reduces tendency to boil and vapor lock the lines. Some use the factory CIS pump, and this requires a good FPR to reduce line pressure and a return line.

To simplifiy my setup, I use a low pressure pump, no FPR and no return line. The carbs see about 3.5 - 4 psi measured after the inline filters and all is well.

Sherwood