Thanks Blak, I am using the Trick Flow adjustable lash adjuster and setting at 0 lash plus .001. Tonight I will re-check my clearance at 111 and since the clearance closes quick, I hope it opens quick as well with retarding the opening point.
I had read that the exhaust port on the pi head was pretty active and the aftermarket ground the exhaust lobe to keep it more mellow. What does the change to 34* do?
They would be surprised to see my cams, I bought them in 2014...
From what ive heard, comp receives old and odd cams for a regrind all the time. They the big dogs of the cam business.
Cams that are claimed " off the shelf ", like what you have, basically are base model cams of desired intake valve duration. When a special grind is desired, the cam closest to desired intake valve duration is pulled off the shelf and reground to desired duration and at most times just regrinding lobe seperation by altering the exhaust opening. Delaying exhaust opening adds that much more of combustion pressure on the pistons top.
Remember valve opening and closing point cut in half relative to the other lobe opening and closing cut in half is lobe seperation angle.
And when grinding the exhaust to a delayed opening 20*, that makes the lobe seperation angle 10* less. In example a 115* lsa camshaft ,regrind the exhaust 20* will make lsa 105*. The lsa refers to the camshaft geometry while the exhaust duration refers to the valve action relative to crankshaft degree.
The pi big exhaust valve and port can handle some serious evacuation while keeping pumping losses to a minimum. Meaning the piston speeds get so great that it begins to push the exhaust out on the exhaust stroke. Given the 4.6l BDC piston dwell time, a very delayed exhaust opening is possible.