[scarceller]

Do you have full cam specs for both cams? The most single important cam event is 'Intake Close Event' (IC) you need to fully understand the importance of this event.

If a cam closes the intake valve later then it means that cam gives up a portion of the compression stroke and dynamic compression is reduced! You must understand this concept and it's consequences. This is why you can NOT decide your static compression ratio until a cam is chosen, pro builders build an engine around the specs of the cam.

So, I'm very interested to know when the intake valve closes for both these cams?

My notes have the 911s cam as these specs
Porsche 911S
Duration at 0.050" 267/235
Lift E/I .459"/.396"
LCA 97

This cam hits it's IC close point at about 50deg ABDC of compression stroke. It gives up 50deg of the compression stroke before compression can start.

This 50deg IC is very similar to that of a 964 cam and we know that using a 964 cam in a single plug engine needs about 10.5:1 compression.