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MG MGB GT V8 Factory Originals Technical - Factory V8 tach ... is 5200 really the redline?

I found a factory V8 tach and put it in my car. Looks great. Its face has the redline sector starting at 5200 rpm ... that doesn't seem like much and it is very easy to blow through now and again. The car has a 3.9 with massaged heads and a cam, don't know what kind of pistons or conrods. Should I be paying heed to the 5200 redline?

I have a 5200 tack. in my 74 G.T. & with a bit of cam & with 85 ft.lbs. on the closed valve spring & I turn it till the tack stops & thin I shift & the motor has 425,000 miles total on it to date. 125,000 sence last rebuild. If you have the right valve springs the stock motor will TURN some R.P.M.
Glenn Towery

5200 was the factory recommendation, and yes, even the standard factory car revs right through it with ease.

Paul Hunt

What's the point in ruining your elderly factory engine by revving through the red line when 90% of the power is available well below 5,200 rpm ??
Colin Hoad

Can anyone recommend a dealer or person or parts to help convert my stock 4cyl B tach to run with my shiny new V8 engine? It is a standard Smiths guage. I think have a spare tach I could use as a "donor" to run car while my nicer one is being worked on, but need a place to get it done..
Larry Embrey

Hi Larry, Take a look on Leon's web site. He has info on converting the tach.


Thanks Kelly, I found his site shortly after posting heh.
Larry Embrey

Thought I'd already posted this once but can't see it so ...

Badly phrased, Colin. I didn't mean to imply that I chose to rev through it, quite the opposite. It *does* rev through it so easily (unlike the 4-cylinder) that I have to watch it like a hawk.

Paul Hunt

This thread was discussed between 14/05/2001 and 21/05/2001

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