1973 Tach and Speedometer w SC engine?
 

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

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

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

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

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.

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.

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.

I was afraid of that.

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.

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.

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

Great thank you. I'll check that out

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.

Sent from my SM-G991U using Tapatalk

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