Retrofitting newer CIS to earlier CIS 911

[Jay Laifman]

First, I'm not looking for anyone to tell me to drop the CIS and put on Webers. I have a just rebuilt 2.4 1973.5 911T. It's got brand new 2.4 CIS pistons in there and rebuilt 2.4 CIS heads heads and cam. It also has a new airbox (close to NLA) and injectors. I've always very much liked the silky smooth CIS engine.

But, here's the problem. The 2.4 CIS T has two pressure regulators: one is the warm up regulator (WUR) one is the throttle position regulator (TPR). Six months later, they dropped the TPR in the 2.7 engine. I appear to need a new TPR and I have not had any luck finding one.

So, I guess the first question is if someone has a line on a NOS or high quality used TPR, please let me know.

Absent that, someone has suggested that perhaps I can retrofit a 2.7 CIS throttle body that does not use the TPR and use a 2.7 CIS WUR. But, there are so many other unknowns: is the 2.7 throttle body too big for the 2.4 engine? Will I also need 2.7 injectors?

And yes, if this direction gets too crazy, the Webers do come back into play - and then I'll be asking about the right Webers/PMOs and jetting for a 2.4 with CIS pistons and cams. The best would be if someone had a good TPR for me.

Thanks for any help from anyone who has any ideas.