It is the vendor's responsibility to send you parts that work. Simple as that. They should know what is in their kit. You shouldn't have to make do, or fabricate parts, or buy new parts to make it work. I live close to CPP but do not use their stuff. Many other suppliers out there.
Fred


1956 3100 Pickup/Red/350/3sp OD/PS/Disc Brakes
1957 Bel Air Sport Coupe/Red/355/TH350/PS/Disc Brakes
2017 Silverado LT Single Cab SB/Black/5.3/6 Speed Trans
1947 Willys CJ2A w/F-Head engine