Hi,
JMHO, but I would not use a 906 cam in anything less than 3.5 litres if it will driven on the road. Thats a very old profile and suffer serious drivability issues in smaller engines. Nowadays, there are FAR better cams,...
If the car needs to be streetable, I would use 40mm carburetors, tall manifolds, and something like a Webcam 120/104 or a GE-60 camshaft. That combination in a 2.5 makes a nice trackday engine that pulls over 7200 RPM with decent manners.
I would recommend that the rest of the engine will be safe to run at 7500 RPM,.......