The standard truck 3 speed of that era used the metal gear which corresponds with the drive gear that is
pressed on the output shaft. Cars used the same transmission with a plastic gear and corresponding drive gear.
I have the car drive gears that I could share. You would have to disassemble the trans to install it.
Send me a PM.
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