One thing on the 452 head dont touch the floor of the intake or the radius to the valve. The 452 out flows the 906 and all the others to 5.50 lift.
We're going to have to agree to disagree on those statements above. I know that Don Dulmage said the short turn on the 452s shouldn't be messed with, but they won't show their true potential w/o work there.
906s have better under-.500" #s than the other standard OEM iron heads. The short turn work they need is to keep the flow from dropping off at higher lifts.
There are still some good threads by Dwayne Porter on porting OEM BB heads stuck out on the "old" Tech archive linked from Moparts' home page, but you have to dig down a couple of levels to get to them.
