IMM Engines 408 build

OK, on the lift numbers. With that lift, the narrowest sweep you can get is going to be a something like .035" to .040" wide. (I'm being lazy and did not take the time compute the exact number...).

You need to forget the idea of the sweep being centered, unless you want to do a crazy amount of machine work. Don't take the info off of websites that tell you to do so. A roller tip being off center does not change the side force exerted on the valve tip 1 iota; that very small side force is the same whether the roller is centered or not.

The only way to get the sweep centered AND the sweep to its narrowest at the same time is to:

1. Change the rocker center height to get the 90 degree angle between the rocker-center-to-roller-contact line and the valve axis, at mid lift
2. Then move the rocker center towards or away from the valves to re-center the sweep... but this require moving the studs which involves a lot of careful, custom machine work and so is not practical in most cases.