3.0 Engine swap - tach question

[cds72911]

Hi all,

Word has it that the tach on my '72 MFI 2.4 will not work with the new '79 3.0 engine. I assume this is correct so I need a new tach for my swap. I have an opportunity to trade tachometers with someone who is doing a MFI conversion.

Will a tach from a 1975 911S with CIS work with the 1979 3.0 engine?

I thought the logic was that the newer tach had to match the 6 pin CDI box. I also thought the 6 pin CDI box came out in '78.

I wonder: Why would a '75 tach (3 pin CDI box?) work any better than my '72 (3 pin CDI box)?

I am concerned that it will not work and better/differently for either of us

Thanks,
Charlie

[CamB]

Once again I wish I lived in the US...

I have an SC tach in my 1975 911S and want to find someone to swap with for the correct one.

Everything is too hard/too far from here (New Zealand).

I guess my car proves you can match an SC tach to a 2.7 CIS though. I have no idea how it was done (a PO thing).

Cam

[This message has been edited by CamB (edited 06-13-2001).]