1973 Tach and Speedometer w SC engine?

[runner4fun]

I plan to replace the existing 2.2L engine and 901 transmission in my 1973 911T with a 3L Sc engine and a 915 transmission. Will my tach and speedometer work or do I need later versions? Thanks

[thetorch]

what version of 915, cable or electronic speedo?
tach may need TachAdapt, no bit deal.

[runner4fun]

915 has electronic connection, no cable. I believe it is a 1979 911Sc 915

[jbell959]

A 73T should have a 2.4 engine and 915 transmission??

[jbell959]

Originally Posted by runner4fun

915 has electronic connection, no cable. I believe it is a 1979 911Sc 915

You will need to get a later electronic speedo. Any of them 76-89 will work

If your tach is a 73 tach it should work fine.

[runner4fun]

Ok thank you. It is possible to modify my 1973 speedo?

[jbell959]

Originally Posted by runner4fun

Ok thank you. It is possible to modify my 1973 speedo?

No. The early ones have a mechanical drive and the later are electronic. No way to modify.

[runner4fun]

my car had the original engine and transmission swapped out at some point. So, free from a numbers matching car, I have a 1979 Sc 915 transmission and plan to build a 3L Sc engine for the car. I plan to sell the 2.2 engine and 901 transmission cheap.

[runner4fun]

I was afraid of that.

[jbell959]

You can look for a 72-76 915 which will have a mechanical drive or swap the speedometer. It's only 2 wires through the tunnel for the electronic speedo, but the needle on the later speedos won't match your other silver button needles.

[runner4fun]

Ok I will replace the speedo with a later 76-89 electronic version and have it painted too match my other gauges. Thank you for your help. Much appreciated.

[phunt]

Dakota Digital makes an electronic to mechanical speedo drive. So you could use your stock speedo. It is just a box that takes your electric feed and drives a little motor that drives your speedo. Easy to find at places like jegs and summit. Like $350

[runner4fun]

Great thank you. I'll check that out

[jbell959]

Originally Posted by phunt

Dakota Digital makes an electronic to mechanical speedo drive. So you could use your stock speedo. It is just a box that takes your electric feed and drives a little motor that drives your speedo. Easy to find at places like jegs and summit. Like $350

Have you used that box in a 911? I was looking at it a few months back but couldn't find anyone that has used one.

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[phunt]

no I have not used one in a Porsche. this is my first Porsche I am planning on using this box. I have used these speedo conversion boxes on past muscle car projects that I have done. they worked well no complaints