[Healeys] Conversion to Negative Ground

[Roger Grace]

I have just converted my 67 BJ8 to negative ground.
Generally all OK except ...
The cut out now seems to be playing up; pops in and out (light comes on and
can hear it) intermittently at medium revs.
This is a new situation after the conversion. Lucas RB 340 regulator.
Voltage is a tad high at 15.5V at 20C at about 3000 RPM
I did read somewhere that this polarity change can stress an old regulator...
??
Now I see that the regulator cover is sealed (no screws) and so canbt fiddle
with the cut out setting; does this mean that this regulator has been
previously changed .. ?? is this unusual ??
Comments from my more experienced Healey colleagues appreciated.
rg