I did the swap and love it. The spill back issues is more gas pump specific.  Some do, some don't.  Also living on the Gulf coast is has its advantages of extra fuel for generators when the hard wind blows. 
 

I have the 22 gallon in my 66 fastback.  I do not notice the trunk height loss since I never drove the car without that tank in it.

If you figure when you are on a long trip that you will start looking for a gas station when you get to 1/4 tank, that  means with a 16 gallon tank, at 20MPG, you have a 240 mile range.  With the 22 gallon tank, you have over 330 mile range with 1/4 tank left.

The tank is approximately 1.5 bladders, because I always have to stop to go to the bathroom before I need gas!

Extra weight is not noticed.  If it was that critical. I would just go on a diet!

I bought a 22 for my car.  Mustangs Plus makes a conversion filler neck for this tank upgrade...fits perfectly!

lowercasesteve wrote:

I have a 20 gallon tank on my '66.  It is great.

One thing. get a sending unit for the size of the tank.  a 16 gal sending unit will not correctly measure your remaining fuel.  I got a 20 gallon sending unit (2 actually)  and both do a better job, but still are show less fuel than there actually is.   Make sure the tank has a plug for emptying the tank.

I can't think of a safe way to adjust the fuel sending unit.  Maybe someone else here can help.

Steve;

I made up a set of gages that  will help calibrate the sender on the bench.  I sent them to Dave K for a test run as he was having gas gauge calibration issues also and I've been waiting to get his feedback before "telling the world" about them.  When I set mine up I dialed it in to read 1/8 tank at 4 gallons in a 20 gal tank.  That seemed to be a good setup for our car with EFI.

When we went to Kalispell we were a ways from Rawlins, WY and I was getting near the 1/8 point so I started hollering on the radio for a certain un-named person who was leading the pack to hit the next station.  He didn't.  So evenually we got to Rawlins and I filled it.   Eighteen point five in a 20 gallon tank and the gauge was just above MT so I guess my cal job was fairly close.

If you want to try the procedure and gages shoot me an email and I'll send the package to you.

BB

Last edited by Bullet Bob (4/30/2013 1:21 PM)

I always figured it is most important for the gauge to be accurate near EMPTY as Bullet said.  I know if I just filled up thje tank it will be FULL.  I just need the gauge to be able to tell me accurately how much I have before I run out.

I have used the poor-boy calibration method with great success.

Install a new, dry tank with a new or used sender/pickup.  Hook up the gauge and note where the gauge reads at KNOWN EMPTY.  Make mental note of reading.

Pour exactly ONE GALLON of gas in the tank.  Note the gauge position with KNOWN ONE GALLON.

Pour in another gallon and note gauge position at KNOWN TWO GALLON mark.

Pour in a third gallon and again make mental note of gauge reading with KNOWN THREE GALLON mark.

There is no guesswork with this method.  You will then KNOW what amount you have in the tank for a given reading.  If you are like me and CRS crops up now and then, write it on a card and stick it in the glove box.  (Of course, you will never remember it is in there)

Use a 70 pickup/sender with the 70/22 gallon tank.
Use a 69 pickup/sender with the 69/20 gallon tank.
Use a 68 sender for 65-68 16 gallon tanks if you want a 3/8" hose fitting.
Use a 65-67 sender if you want the 5/16" hose fitting.