Did you speak with a young buck on his computer at your local NAPA or an old boy who knows how to use his old catalogs and parts books?

This can make a huge difference. Those veterans are pretty crafty at finding those elusive, “obsolete”, can’t find ‘em, parts.

My guy’s name is Doug. He’s good.

This is a C20 setup. I did mine back in the mid 90's, I cringe at trying to find the bushings now.

For sure the veteran parts people are great at finding the stuff in the books.

Rant, Recently went to AutoZone and Oreilly's to get brake hoses. Granted I have a unique setup now because of the front disc conversion, but the hoses are stock hoses. I figured out the year I needed, they showed they were in stock, and this was at both stores, each kid walked around the back for 10 minutes searching for the elusive items. They couldn't find them. I left and went back to AutoZone about an hour later, got the manager, he got the rolling stairs, rolled them over, climbed up, pulled out the bin, and grabbed the hoses. Unfortunately they both didn't have the correct copper washers, one was correct, the other was metric, and they don't have a box of them, only the packs of various sizes so you end up with a bunch copper washers you'll never use. I said no sale because of the washers.

HAH! Sorry for chiming in here, but...
I know what you mean. I just attempted (front) wheel cylinder replacement on my '64 C20. I got the cylinders 4hrs after ordering them, and took 'em home to replace them. I strip the front wheels to the backing plates, and remove one of the wheel cylinders, and replace it, only to find that the long barrel fitting on the (newly replaced) brake line does NOT permit reaching the (metric) bleed nipple on the new wheel cylinder(s). It's a 9mil, and short. As a result of them being metric, you can NOT use the original (long hex) bleed nipples. BAH!
If you still have your original wheel cylinder(s). Keep them! I have the number for a couple of manufacturers (BENDIX being one) that still make the correct replacements.
In the end, I just opted to rebuild them. The cylinders weren't so bad that a good cleanup, and rebuild wouldn't cure (and did).

Why did America create SAE, if they weren't going to continue use it?!

Chris

ACDelco wheel cylinder rebuild part number (all 4 wheels) ACD# 18G5

also try autogeek.com and rockauto.com