Think this question applies to any Jag converted to a Chev V8 when the original engine was SIX or TWELVE cylinders. The tachometer in the original car was therefore calibrated to read the RPM or the 6 or 12. So, when a EIGHT cyl. engine is installed, is the tach going to give an incorrect reading?
Case in point, my own Series II XJ-6 sedan (happens to be a '78 model but don't think that matters). It had the engine and trans installed from a '71 Camaro back in the 1980s. So a very typical "350 conversion". Does my tachometer still think it is reading RPM of a XJ-6?
Bottom line: Is my 6 cyl. tach reading correctly for the V8 engine under the hood?

 

IF the conversion was *properly* done, the tach would have been modified too.
They should have replaced the stock (.068) capacitor on the tach, with a different one, (.045).
The component should be marked as to its capacitance. You might have to pull the tach to see.
If the cap is .045 then you're all good.

Although, I would think if you're driving the car very much, you should be able to guess by now if the tach is hinky.
(';')

 

LNR, that’s for the xjs, the xj6 just gets a resistor,

OP, go to Jaguarspecialties.com and look at the tips for working on jags, In there you will find the instructions on how to adapt the tach, including pictures!!!

 

Thanks y'all.

 

Um, OK, Darren, I will stand (or sit) corrected.......