[OrrieG]

Without photos I am still confused. I thought all GM boosters and MC had the same bolt pattern the differences were the diameter and length of rods/arms between the pedal and booster or MC? On my truck I had to custom fab everything but am now on MC #3 with no interchange problems. Linkage can be solved, it might require spacing the booster off of the firewall to gain clearance for rod fab? Post a photo of what you have for pedals and firewall situation so we have more information.