JerryVV said:
Also if one wants to lighten a flywheel there are instructions in the black Competition Preperation books that are available as re-prints from many sources.
Do you have a page number, Jerry? I can't seem to find any instructions in my copy of either the black TR4/4A Comp Prep or the earlier dark blue TR3/4 Comp Prep.
The earlier one lists the lightened flywheel with a part number; the later one just says to use an alloy flywheel.
The closest thing to instructions that I could find was in the much later "Triumph Preparation Handbook" with the white cover. But it only says that you can mount the flywheel in a lathe and remove about 4 pounds, no specific instructions on how to mount or where to trim.
It also mentions that there are two flywheels for the TR3 and TR4, with the earlier one weighing only 21 pounds. I think this must be a reference to the optional lightweight flywheel (P/N 132766) as I recall the early "press fit ring gear" flywheel being heavier than that.