There's been a lot of discussion about cam specs here, lot's of it pretty technical. Some of it I understand, at least the basics, of lift, overlap, measured height. More duration seems to come with more lift, more overlap causes rough idle with lower vacuum. Lobe centers, which I assume is the center-line difference of intake and exhaust, fully open, confuses me a bit. I've degreed in cams, but aside from following the instructions ( it seems they were normally retarded a couple degrees) I don't really understand what that means or accomplishes. Why not just grind it to go in straight up. Looking at Mummert's site, he has a 280-I-07, and a 280-I-11. The difference appears to be the lobe centers at 107" and 111" respectively. On a street V-8, of say 300 CID, what's the difference driving from, say 1500 or 2000 to 4000 or 5000 rpm? Assuming the heads, manifolds etc. are the same, and compatible to the cam, why does it cause the difference? And finally, how do (real general here) bore stroke/ over square/ under square affect this? I don't like to seem too dumb, but I'm pretty sure I'm not the only one, and there's so many combination out there, there must be some differences of opinion even among cam designers. How about a little remedial education for some of us.

miker
55 bird, 32 cabrio F code
Kent, WA
Tucson, AZ