IIRC from the Reed cams I had, 300 and 310 are the duration, 5A2 means it is ground on 105 with 2* advance.
This guy used to work for Reed and might could help if no one has an old Reed catalog-

http://www.demoscams.com/

Thinking back, my last 340 cam from Reed was 300-310. Can't remember the lift but it was wicked with the 3.91 gears and a 4 gear.

Tim