I used a Suburban/Blazer(40gallon) tank on a 54 I did for a friend years ago. You'll have to move the rear frame brace to the very rear of the frame, put a brace in front of the tank & across the top to hold it in and I used the stock Burb gas straps to hold it in from the bottom, trim the frame on the sides so the tank would fit w/a 40gallon tank (a smaller tank you may not have to) along w/boxing a small part of the frame & put a "U" shaped gusset on top of the frame where the filler neck will go. And yes the filler neck was in the rear fender, sorry no pics...Joe
