This is from your profile
Right now you have $3500 into a car that is worth $2500 if it was running driving. Remember to walk before your run....
The 7.25 rear end wasn't broke. So run it and fix the other stuff that is broken worn out. Use patience and time to your advantage and at least figure out what drum to drum A-body sure grips go for and wait on a good deal under average selling price. Sounds like you paid $800 plus for the rear end. If so, an average price. But that could have went to your front end and/or gas tank to get your car in running order.
Objective is to get the car running. Disregard improvements unless they are part of fixing something (727 trans) or you walk into a great deal.
See if you can find a good used 67 gas tank somewhat locally. Maybe you can get one that you can look at in person and get for $40-50, maybe less. Clean it yourself.
Do you know the Mopar scene in your area? Meaning all the guys that sell used Mopar parts, the guys in the club, the shops that specialize in Mopar stuff. It takes a while, but it is really really helpful. You will get a feel of who to deal with, under what terms, and who to be careful with. I would really suggest going to a Capitol Cities Mopar club meeting:
http://www.capitalcitymopars.com/Clubinfo.htm You don't need to go to every one of their events, or go to any. But asking questions before, during, and after a meeting can be really helpful.