Around 268 degrees of duration where the "Magnum" cam series begins is where a noticeable idle lope starts happening, and power brake and other vacuum-related problems begin. A programmable computer chip that allows for some tinkering with fuel mixture and ignition timing advance is also helpful.
Jerry
Yep, vacuum issues was another thing I was trying to avoid. I'd sent off my chip to be reprogramed with the new cam specs. It should be back today.
