serpentine belt drive HELP?

[Firebird 68]

I am building a 1967 Chevy II that I have installed TCI front and rear suspension. I am trying to find a GM Performance serpentine belt drive system with a/c that will fit my car. With the engine (LSX 454) and trans
(6L90E) installed I have 11'' from the center of the crank to the passenger side frame rail. I was wanting to use the GM Performance part #19155066 which is for a 2006 CTS-v but I would need 12.5'' to the frame rail. Does anyone know of a GM kit for this? Any help would be very much appreciated.

Thanks Matt Stinnett
Choctaw,OK