V-8 trucks of that era would have had an 11" clutch and used the same bellhousing as the 6 cyl. Since you will need a different flywheel for the later engine as it has a different size bolt pattern on the mounting flange, purchase one that uses the 11" clutch. Get a clutch kit for the year of the truck with a V-8.
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