I wouldn't recommend buying the brass syncro rings unless the shop has a good understanding of how to
install them correctly. The procedure includes staking the brass rings into the housing to secure
them. I have had that era syncro assemblies rebuilt by Anaheim Gear in Anaheim, CA.
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