JimmyD1333 - First things first, you need to know I like old race stuff, I like to look at old race stuff, and I like to see old race stuff preserved. Your question to save this chassis or build new, and then; what would be safer and more cost-efficient? Racing is dangerous, events can happen to an old restored vehicle just as easily with a new modern vehicle.
Your Uncle taking his fed to a nhra chassis cert is the first advice probably all of us here would have recommended. The question is did your Uncle do this back in 2008-2009 or recently. If it was done recently, very good. Now you know what it needs to cert to 7.50et. Adding the extra bracing and repairing the crack (?) by the motor mount if done properly will assure the chassis passes nhra cert. Obviously this would be the most cost-efficient route, as this chassis already has run and all the part are there and fit together for a complete running vehicle. Properly replacing any failed tubing and adding bracing to a racing chassis is not that difficult for a competent shop.
To build a new chassis and all that encompasses will take more time and money. I'm guessing $10 to $20 thousand dollars depending on your parts selection and how much of the work you do yourself.
I think the NHRA Hot Rod Heritage Series did run at Tulsa. I'm not sure they still run there, but is the NHRA Heritage Series Group 2 what you are interested in running? You will have to do a lot of traveling to run that Nostaglia group. If you are racing with a local group at Tulsa, that is a good way to start and have fun. Also, you do not need to go 7.50et starting; running 9s at 150 in the quarter is plenty fun in a fed. Alan
p.s. Merry Christmas to all!