My race bike had the un-finned Goldie vented drum. If set up well it's a pretty good brake, altho' it helps to have a good cable & strong right hand! They do get hot (enough to get the paint peeling) & fade a bit on track. On a 350 it's not so bad, a 500 would be harder on one so I expect the finned post '66 version would be an improvement. My Road DBD (un-finned 8") doesn't stop on a sixpence that's for sure, even with 2LS brake plate. That said, it is quite a bit heavier than a race bike.