Ray I will try to help.
1) No dealer will probably due this kind of work nor would I allow it.
2) Make sure you have a copy of the current 05 NHRA tech specs for the exact cage needed.
3) Sources for cages that are custom built are usually race car fabrication shops. To find them you need to network. Talk with other people with cages ie NHRA members,SCCA,PCA,NASA members etc...
4) You can buy them pre-built but you must make sure they pass inspection. Good companies for this are Autopower and Kirk Racing Products.
5) Before you allow anyone to do cage work on your car you need to look at prior work they have done.
6) Here in Atlanta there are alot of people that can do work but very few that you can trust. I spent 3 years designing the cage I wanted and then had to have it re-done because a nationaly known Mustang performance shop here did a poor job that could have killed me.
7) Be prepared to pay for quality. Good cage builders have plenty of work and know what they can charge.
8) Again shop around and talk with everyone. Good Luck
