2.4 CIS cam options?
 

I'm rebuilding the top end of my 1973.5 CIS to fix #1 compression issue and oil leaks around the rocker shafts. I'm going to reuse the original P&C and retain the CIS induction system for now.

Looking at Wayne's book, some of the 3.0 SC engines can benefit from a 964cam. So I'm wondering if the 2.4 CIS can benefit from a later 2.7 CIS cam like the 74-77 S/Carrera 911.105.143 & 144. Has anyone tried this?

My main concern is that the original 8:1 compression would be further reduced by later intake closure. This car is strictly for street use, so I don't want to lose torque in low rpm range... but sure would be nice to have it push above 5500 rpm!

Hello Bus,
I am also rebuilding a 73.5 cis motor and was somewhat puzzled when I discovered that the cams in the engine were the 143 and 144 2.7s cams. The car is new to me and I am not sure of the why's or how's of the cams, but I would assume that since they are the closest to the stock cams they work. The car ran before I tore it apart,(low compression and leak down #'s on #1 and #4).
Good luck with your project and look forward to reading what others here have to say on the topic.

Gib

The cams can be upgraded to CIS S cams and set to S spec. Any other cams wont work for your application.
Bruce

Thank you for the guidance :)

I found a good set of 77 towers complete with S cams and rockers, so I am probably going to give this a try.

Should I expect any torque reduction at low rpm or is this effect negligible?

-Van

Flat6,

Does that mean that when setting the cam timing, one would just use the spec for the 2.7 cam as if it were going into its original engine?
I was wondering on my own build what the gauge numbers were for cam timing, but have not gotten that far with it yet.

Gib

Yes, the cam setting spec follows the camshaft.