TR6(PI) Valve Springs

[Don Guthrie <don.guthrie@xtra.co.nz>]

I'm modifying my '74 "late" spec TR6 PI to the earlier 150bhp spec (cam
profile, fuel metering, and valve springs are the main differences). Rimmers
catalogue states the early spec had single valve springs (ie no inners),
while the later had both, but an early TR6 PI owner here swears his came
with double springs.

Which is correct? Or more importantly, which works best?

Don Guthrie
'74 TR6 "Betty Blue"
don.guthrie@xtra.co.nz