Seems H&C are set symetrically ,
http://vintagebikemagazine.com/wp-content/uploads/2017/08/HarmonCollins.pdfTheres a few mentions in early 60s Cycle World , Desert Racers & Flat trackers .
Heres some other blather ,
https://www.classicbritishspares.com/blogs/news/best-triumph-camshaft-set-upthe LIFTERS are where youre gunna get got . Apparently the thruxton cam was the old T-Bird Cam , With LARGE RADIUS LIFTERS .
A lod mega racer , had said they / He , put ' FLAT ' followers in a speedway chair T 100 . You had TO WATCH that the Lifter Lower Corner
did not dig into the cam lobe flank .
Id think a few trial assemblies - a case half , barrel & followers . or if youve a past it barrel , take a hacksaw to it , so theyre observable .
THE OLDE .020 clearance , for mucking about with openings and closings . To Late on the ex & to Early on the int & theyll tangle .
No Way would I set the valves back in the head to get the clearance on overlap . but HELE did on the 500 racers for the Daytona Race .
Hopefully someone'll come up with the Exact specs for that number camshaft .
CAN YOU TELL US What the LIFT Is ? .
or 
