5 spd into 4 spd TR-7?

[PScales <pscales@blvl.igs.net>]

Has anyone tried (successfully) to replace their TR-7 4 speed gearbox with
a five-speed unit?  Mine is a 1976 with dual carbs, and it runs well, etc.,
but the engine is turning a bit fast on the highway (ie, 4400 rpm at 140
kmh).  I'd like to bring the revs down to about 3800, if possible, at
highway speed.

Is there a FAQ somewhere that might describe this change?

People with 5 speeds: what rpm are you turning at highway speeds?

Thanks gang,
Peter
Trenton, Ontario