I understand the Spectra Premium F30 fuel tank will fit a '71 Mav, but it's to be ordered for a '74. Will it be an exact fit? From what I've read, if it does fit, I'll need longer carriage bolts--how much longer? Also, will the fuel gauge read correctly? Will the filler tube from the '71 fit in it? Thanks!
The spectra tank is similar to the later years so it is actually the correct one size wise. So yes it will work for a 74, but as for everything else it should all be fine as far as I know. Atleast that's what I found when I was looking into this route.
You'd need the straps for the larger tank (not just the bolts), and you'll have to re-do the fuel line where it connects to the sending unit. Other than that, it bolts in. Filler tube is the same. The vent on top is different. It will also be right up against the rear valance.
I put an F30 tank in my '71. I purchased the longer ST99 straps and reused my original bolts (or you can reuse your straps and go with longer bolts). I elected to replace my sending unit with a stainless steel one just to start fresh, but I ordered it for a later car (19 gallon tank, NOT the 1971). You will also need to purchase the roll-over/vent valve and grommet for the top of the tank, as your 71 tank vent valve is held in with a small lock-ring. My car had a 3/8" sending unit, so be sure to check what size fuel line you have (5/16" or 3/8"). Basically, the bottom of the F30 is bigger (deeper) than the original 71 tank. Your original sending unit will still work, but when it reads "empty", there will still be a considerable amount of fuel left in the tank, so it won't be very accurate or reliable that way. The F30 will also hang down below the rear valance due to the shape/size of the bottom of the tank.
done this on at least 4 F30 tanks. I just used longer bolts (stock straps)... the fuel line was the same...valance was not an issue...you can adjust the float to read empty.
You will need an inch longer strap bolt. Best I can remember the next size longer was 3 inches longer and had to be cut to length.
William 623, Crazy Larry, Paul Masson, 71gold, rthomas771-- Thank you all for your advice! Paul Masson, you wrote, “Your original sending unit will still work, but when it reads "empty", there will still be a considerable amount of fuel left in the tank, so it won't be very accurate or reliable that way.” Although it won’t be accurate, it seems to me to be a win-win scenario, less of a chance of running out of gas! 71gold, you wrote, “…you can adjust the float to read empty.” I wouldn’t know how much to bend the rod, so I think I’ll just keep it as is. Mr. Masson, you also said, “You will also need to purchase the roll-over/vent valve and grommet for the top of the tank…” Is there a part number I can refer to? Looks like I can get the Spectra Premium F30 Fuel Tank from Amazon along with the Spectra Premium ST99 Fuel Tank Straps. Will I need the F6TZ-9B076-AA Fuel Vapor Valve Seal? Is that the grommet? I very much appreciate all your help! Renton5
I'm gonna have to stand corrected on the longer straps. That's what I used when I did the swap (swapped it back to the 15-gallon tank), but I didn't know you could just use longer bolts with the existing straps.
for anyone that wants to do this...I put 2 gals. of gas in the tank then tweeked the float to read empty. that way I had 2 gals. on empty.
Hey Frank, can I assume that would also work on the stock 15-gallon tank? I hate how on my car, the second that needle touches "E", you're walking.
Here's an update: Although physically, I know a later '70's tank will fit in, but I'm not liking the idea of it hanging below the rear sheet metal. I've decided to get the tank refurbished--it will cost a whole lot more than buying a tank, but I don't want to change the look. I appreciate everyone's comments and suggestions!
