Nice little video of a 944S2 with the cam chain tensioner mount snapped off the head when the pad/chains went. He rebuilt the head himself for the most part by creating his own tools to weld new aluminum on the head and bore out the tensioner screw holes.

 

Actually, with 968's they updated the design on the chain tensioner. It was now triangulated, instead of just 2 mounting holes, one on each end on the S2. As shown, the S2 tensioner could sheer off the head in some instances. In a 968, if you break either of the tensioner pad, the chain will become too long and start catching the cam gears. This will make the chain snap as well as take some cam teeth with it. Seen this happen before. Usually, there are tell tale signs when the tensioner pads are going (lots of top end noise from cam chain). Unfortunately someone I know, heard them yet decided to drive the car down from MA to NJ and paid for it dearly. We found broken teeth on bottom of the oil pan.

The 2 heads, their cams as well and tensioner pads are not interchangeable. The tensioner on the 968 also works the variocam by actuating the tensioner either up or down, hence changing the timing on the intake cam in reference to the exhaust cam. One of the many advances made on the 968.

 

Not fully interchangeable. You could run s2 cams, chain, and s2 tensioner (mounted by 2 bolts) in a 968 head though couldn't you?

 

Not 100% sure on that. My assumption would be the mounting holes would not match, but again, that is my assumption. Don't have one handy to compare.

 

This is back from the memory bank, so it could be tainted but a 968 head has an additional port for a sensor in the middle on the intake side. The S2 does not have that.

 

That's what I figured but I wanted to make sure. Thank you!