looking for suggestions on installing a pick up wooden bed. and gas tank . Frame is a 48 Mercury Not sure what gas tank would fit with filler neck an issue no room between cab and bed . This is a 1938 international sectioned on a Mercury frame,
Not sure I got ya.... under bed? Under bed could be a big challenge. What about going "easy"? http://www.speedwaymotors.com/Spun-...4&cadevice=c&gclid=CM-76qWivsQCFQaRaQodFScAGg
A tank for a 46-48 Ford or merc ought to fit under the bed at the rear if you didn't shorten that area of the ch***is but you would need to relocate the filler neck to the driver's side rear fender.
Might look at a 1965 mustang tank, the filler neck will need to be moved. The tank mounts along the outer flange l, it's pretty simple to build a frame to support it. $100 from summit.
i used an '82 ford pickup tank under a '37 chevy pickup. it mounted under the cab, between the driveshaft and frame rail. the filler went up through the floor under the seat and out through the original fill hole. the sending unit was accessible through a cover i made in the floor. i built it with a six cylinder, if you are using a v8 you will have to run single exhaust.
a35 chevy truck tank fits between the rear frame rails and the neck comes out on the right side just behind the fender in the bed side. holds 16 gal
Installing a wood bed.... With the way your frame is kicked up into your bed you have your work cut out for you. I have seen raised wood beds on pickups that look terrible. It just doesn't look right that way. Just a thought... Steam and bend the wood boards to the contour of your frame. As far as framing for your bed that is easy. Screw on some angle along your bed sides at the frame contour and attach square tubing as the cross pieces to attach the board.
The bad news is as you figured in that you aren't going to have a lot of bed to carry anything in when you are done. I guess you could get a bit artsy fartsy and Make the area from the kickup for the axle forward look like a built in tool/work box with the area behind the frame kick full bed depth to have a bit of carrying room and rig the forward areas for battery on one side and a hand made to fit the spot gas tank on the other. Other than that as far as stock gas tanks you might dig out of another rig and use Tanks inc. shows their measurements for tanks for a number of rigs and shows photos so you might find one that fits in the area behind the axle that way. http://www.tanksinc.com/index.cfm
Looking at your pics again, the bed is below the bead on the back of the cab. Raise the bed up so the front edge is even with the top of the bead on the back of the cab. That should get you about 4 inches of bed depth. Consider cutting out the arc of the frame over the rear axle and using square tubing parallel to the ground, you'll still have the same axle to frame clearance bit gain an additional 1-2 inches of bed depth.