How To Tell What Type P&Cs
 

The previous owner of my 1976 911S told me that when he bought the car from its first owner it had "hot cams" and Webers. The second owner wanted to make the car as stock as possible, so he replaced the cams with mild cams and installed CIS in place of the Webers. I am interested in building a 2.7 RS spec engine (with Webers) and would like to know what my current pistons and cylinders are. I'm hoping that because the car had hot cams and Webers previously, that it has the 2.7 Carrera P&Cs. My question is, how can I tell what my current P&Cs are without taking the engine apart. Is there a tell tale sign. I assume that because it had hot cams that it may already have the more agressive P&Cs. Any info is greatly appreciated. Thanks

Ruben
1976 911s 2.7L

If you knew what you were looking for, I think you could "feel" out the shape of a CIS piston thru the spark plug hole with a stiff wire. Fiber optic camera also comes to mind. And you can "cc" the chamber with ATF given a few tools. At least you could figure your CR.

Thanks for the reply. What is the shape of the top of a CIS piston? How is it different than the Carrera RS piston? Also, what does "cc" the chamber with ATF mean?