IMM Engines 408 build

mullinax95 said
Yeah I've read Mikes articles and used him to correct my geometry on the cuda with Eddy heads.
Upon removing the 1.6 Engine Pro adjustable roller rockers (Chevy rockers) for the supercharger cam I noticed the sweep is centered perfectly but the sweep pattern is wide on the valve tip. I need to contact Mike but have not had the chance.

Any ideas on what would be the adjustment to make the pattern more narrow without interference with rocker center?

Your narrowest sweep will occur when a line between the rocker's center and the contact point of the roller on the valve tip is 90 degrees (perpendicular) to the axis of the valve with the lift at mid lift. Being off-center with a roller is not of any consequence as long as it is not waaay off near the edge. That is why the advice to center to roller on the tip is plain foolish: when you do that, you can move far away from the optimum geometry.

Think of it this way:

With a certain valve length and lift, then the rocker's center HAS to be at a certain height (to get that 90 degree relationship described above).
Once that is set, then the ball/socket is set at a certain height and that fixes the pushrod length.

Not sure what you mean with the last statement about 'interference to the rocker center'??? If you don't want to move the rocker center then you have to change the valve length. Then you get into the optimum ball and pushrod cup location for geometry on the other side of the rocker; then the pushrods may change. That is an issue with all of these rocker setups: you simply have too few adjustments available to make it optimum without moving centers of rotation or valve or pushrod lengths.

BTW how much lift do you have with that SC cam?