I am researching information regarding gas tanks as I want to relocate mine to under the bed of the truck. For those of you that have made this change, could you please advise on anything I should be aware of or on the look out for regarding buying a gas tanks. Would be really greatfull if you could share what tank you used in your bulid and why.
We used a 1970 22 gallon Mustang tank. This increased our range by 40% or so vs. stock - nice. It fits out back under the bed with the fill spout through the bed. Jniolin has a nice write- up on the installation. You have to build a little rack for it to sit in & in our case we had to move one bracket under the bed to get enough room.
We got our tank from Rock Auto for about $120. Then you get the sender unit for that tank as well. The tricky part for us was that we modernized our gauges & they all used a ohm - 200ohm range for full to empty. The mustang sender unit used some other scale like 11ohms to 78ohms.
Eventually we bought a modern universal sending unit & welded it on the
'70 sending unit & everything works fine.
Before you decide on a gas tank behind the rear axle, plan out your exhaust routing. If you want a rear exiting exhaust, the rear tank can be a problem. On my 49 I am staying with the original tank since I wanted a rear exit exhaust. I suspect many go to a side exhaust when using a rear, between the frame rail, tank. Depending on your rear axle choice, you can get space constraints for rear shocks. Lots to consider when you make a change!
Bill is correct in highlighting that when you make changes it generally effects other things as well - tradeoffs. We like the bigger tank out of the cab & out back under the bed - but we had to go with side exit exhaust. You also have to change the shock perches to fit around the tank - but it's not a big deal to move them & weld them back in. After some complaints from the female side of the family I also added a charcoal filter to reduce the gas tank venting fumes in the garage.
This project is a (1) or (2) weekend job - I'd say a more than one six pack job.
Unless you have a leak, or are sloppy when fueling, there should not be any fumes in the cab. The disadvantage to the cab mounted tank is it steals a couple inches of legroom. Removing the tank from the cab allows the seat to go back further, and/or gains storage space.