[Will]

Originally Posted by pmd400

Iv read this whole thread, it's very interesting.
In a 9.5:1 iron headed 455, a cam with a 274 adv duration and 230 at .050 is considered to small. It doesn't make as much power as it should and is octane sensitive.,,,

I think this might be oversimplifying things a bit. Lobe centerlines play a very large role also as they determine valve opening and closing points in conjunction with the overall lobe profile. A fast-ramp cam like that might work just fine and have a broader powerband if modified to a 112 LSA and 108-110 ICL. Of course, the faster ramp cam will still have later opening and earlier closing points than a cam with similar .050" duration but longer seat duration ("slower" ramps) and the same lobe centers.

Isn't the point of a roller cam to minimize the seat-to-seat duration in relation to duration and lift off the seat? In that respect, a fast ramp flat tappet cam is an attempt to mimic the valve motion of a roller as much as possible. Of course it seems that running bigger rollers (as measured at .050" duration) than flat tappet cams is the way to go.

Which all comes back to valve opening and closing events and their relationship to other engine parameters being the key to whether an engine is a dog or a monster.