okay here it is short and sweet.

want headers on my 1966 225 A body Dart.

Mopar has headers for A bodies After 67.
Same with Hooker.

How different are the frames from 66-67?
How much modifying might, if any, be needed?

Is there anyone else (other than clifford) that I can turn to for headers?

caesar

I think Clifford is your only choice. Many people like the shorty style headers, and they are nice. I had the full length Clifford headers on my 65 valiant and they fit very well. No real problems.

Rick

I say go for Dutra Duals. Same cost, guaranteed fit, less of a headache to install and maintain.

Reed