In my interweb research, I found this information regarding secondary rod hanger adjustment.
I tried it, and it seems to work fine (for my Non-performance application). It kind of makes sense, but does it work?
"You've read all about the different letter numbers for the secondary hangers, and how a Y hanger will make your car faster than an M hanger or whatever. Fact is, you can bend and adjust any hanger to any hanger height you want, so it doesn't make a heck of a lot of difference what hanger you choose to use. Just get it set up right:
With the secondary air valve held wide open and the secondary rods pulled all the way up, measure the distance from the top of the rear wall of the choke horn to the secondary rod hanger hole in the hanger. This distance should be 41/64. Bend the hanger to adjust. You have to adjust each of the two sides independently. You now have a performance rod hanger."
