If intake valve lift is the current limiting factor........................
Why dont I recess the intake valve seats in the head say .080" and use a .080" shorter valve?
This would back the compression off a little also. It may shroud the valve a little, but I would clean up the chamber around the valves to allieviate the problem.
Combine this with say .030 machined out of the valve relief in the piston, and you should be able to approach .500" lift.
Now I realize that recessing the seats .080" may or may not be too much but there is something there to be had. Whether its .055" out of the seat and .045" out of the valve relief, or whatever.
While I am at it, why not larger valves?
I think you will find that as you increase airflow, you will get more air in the cylinders at the same boost, thus keeping the air charge cooler, which = more power & torque.
Just remember where you heard it first....;p
I need to get my low mile bone stock 6.9 w/studs back in my rig first, but then I am willing put my money where my mouth is and hotrod the hell out of a set of idi heads using the ideas I just desribed. But I will still need a custom grind on the camshaft. I wonder how much a good cam grinder can remove from the base circle of a factory or logger cam? Or maybe copy an existing profile already in use in another brand of diesel engine?
