thanks guys here is some helpful info i found: might help someone on a search.

Cams with up to 220� of duration (measured at 0.050" cam lift) are usually best for stock unmodified engines. Once you go beyond 220� of duration, intake vacuum starts to drop and idle quality suffers.

Another spec that affects driveability is the relative timing of the intake and exhaust valves. This can be expressed either as "valve overlap" (the time during which the intake and exhaust valves are both open) or "lobe separation" (the number of degrees or angle between the centerlines of the intake and exhaust lobes). Decreasing the lobe separation increases overlap, while increasing the separation decreases overlap. Most stock replacement cams with durations of less than 200� will have lobe separations of 112� to 114�. Higher duration cams for mid-range performance typically have 110� to 112� of lobe separation. With racing cams, you'll find lobe separations that range from 106� to 108�.

Overlap occurs when the intake valve starts to open before the exhaust valve has finished closing. Increasing overlap can be a desirable thing in a higher rpm performance application because the outgoing exhaust actually helps scavenge the cylinder to draw more air and fuel into the combustion chamber. But too much overlap at low rpm kills low-end torque and throttle response by excessively reducing intake vacuum.