The M4F isn't much of a cam for the 261. It is real close to the stock 261 cam, which is the cam used in the vette 235. I don't recall the grind code in my freind's 261, it is what we used to call a full race cam. He got it from Patricks, some 10 years ago. I have the M4F in my 235, it is what was called a mild, or 3/4 race cam. It still has good low-end torque, and I have had the engine up to 4,500 rpm. For comparison, the 261 has exceeded 6,000 rpm.
