I seem to recall that some of the R-model Racers has a larger 22 gallon tank. Might check with Tony Branda Mustang. I know the 16 gallon Fuel-safe is almost drop in. Someone else on the VMF installed a 22 gallon one. If you can get one that ius the same size, just deeper, it should be an almost drop in...but you'll have to get the sender going, possibly a pump, etc..not sure...Kory
I'm running the Fuel Safe 22 Gallon. Another path to take is installing a 69/70 tank. Both of these gain the extra capacity by "going up". Instead of being flush with the trunk floor the tank actually rises up above the flange. You can see it here...
When you add a part that wasn't originally available for your particular model, it's no longer an "upgrade," it's a "modification".
However, should you choose to modify your car by adding one of the 20 or 22-gallon tanks available for 1969 or 1970, it's a simple bolt-in procedure. Then only modification you might need to make is to remove a short portion of the filler tube if you go with the 22-gallon model -- and don't forget that you'll also need the appropriate sender for the tank you choose.
The PO of my car was kind enough to put a 20 gallon tank in for me. I just wish they had picked the 22 gallon instead, LOL
I don't think they had to modify the filler tube.
[color:red]1966</font color=red> [color:blue]V8</font color=blue> [color:red]Coupe</font color=red> http://www.geocities.com/2bav8
5 speed, 4.11s, 10.13 in the quarter mile.
Oh wait, that was a Sammy Haggar song...
The conversion is relatively simple but a few extra parts are required.
70 22 gallon tank & 70 sending unit
The 70 sender uses a 3/8 fuel hose, your 66 has a 5/16" line. You can either make a brass adapter from auto parts store pieces or convert the long rear line to a 3/8" (parts is available ready made). You will also have to contend with the mismatch between the filler tube and the tank inlet. I had my tube rebent by a muffler shop and tweeked the inlet a bit. It worked great. I currently use the fuel line reducer but will install a new 3/8 line shortly.
As far as the Fuel cells go, a 22 gal Fuel Safe is an option for the 65-66 and a filler tube is available to fit it. Give me a buzz if you need more info.
National Parts Depot
1965 Conv:Street driven concours
1966 Coupe: Daily driver and toy
I did this mod on my '65 convertible with a '69 tank (20 gal). I really didn't consider it easy. Bending the filler tube, and bending the tank inlet up to match the angle of the filler tube made the job more difficult than I like. Then there was the issue of the fuel line mismatch. I'm happy with the results, but it was not easy.