yer barnes rear hub is pre 70 brakeless, braked pre 75.
Redline would be after 74, not sure when XL came out, aces type triples, so out of all them bits you could just picked the latest bit and call it done. Still be Pre 75 racing.
Ali , firkos right, prity shit. i only have mine on cause i love the reversable flip QA hubs, but as far as braking they have a 20 cent piece disk as a pad and you would be better off sticking your foot on the front tyre, They were originally used in the 60's on machines to slow rotating parts, i thing industrial type presses and lathes etc, then found there way onto Karts and light air kraft, then onto bikes in 72'.
They still sell airhearts for the machinery applications new today, but Flat track bikes went onto Grimica types, and now they just run stock MX or the later nissin or similar types with an actuating arm or rod push and small master unit