If this is a manual transmission application, you may be using the incorrect bellhousing. The truck bellhousing
has one hole on each side located at about a 45 degree angle to match the cross member.
The early car bellhousings had 2 holes on each side and used a completely different mount configuration.
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