Tommy,
You will need to bend or modify the shifter arms on the side cover of the (new) trans to come as close as possible to replicate the configuration of the original trans. You will also need to bend the shift rods to match up with the modified shift arms. It may take a number of trips under the truck and to the vise to get it right.
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