I run a Poston 107 cam. The only reason for me is because I wanted a cam that would pass emissions (my stock one needed replacing during a rebuild) and provide a little extra performance. If you search previous post about cams, most will say that you really don't need to change cams to get to 12s. The 107 cam idles smooth, and seat of the pants acceleration seems okay to me. Now my combo is coupled with Chevrolet 1st racing design camshaft valve spring (just a touch heavier than the Poston recommended spring), but Poston said it woud work fine. With regards to emissions, non-attainment areas of CA test for NOx and as the lobe center (LC) number gets bigger, so does cylinder pressure and that may increase NOx. The other cam that is close to stock LC is the ATR RP313B and the Lunati 200 camshaft. I thought the lift was a little high on the ATR cam, and the price was better for the Poston cam as opposed to the Lunati cam. I currently have approximately 15000 on my new engine and it runs great. The car recently passed the smog test pretty cleanly. So, my goals were met. Also, I'm in the 18mpg range.
