Oh, using me as the guinea pig I see
My first try is going to be to shorten the collector. I think the collector hitting the frame is my only obstacle.
But since the exhaust has to go under the frame anyway, I might just stretch the primary tubes so the collector will sit under the frame. I ould try that first but it will be hard for me to weld that back together. I can MIG but I'm no professional.
I'm at my parents house now so I'm gunna check to see if my 1960 Buick centerlink is the same as Pontiac. Once I get this figured out and painted and then installed the motor will be test fitted.