Pulled this out of a 389 Pontiac. Looking for specs, valve lash, etc... I think it was installed around 64' could be older. info is: Isky 505C CY67 magnum 4P 08 hardface
Ran a 505C ina 64 409 for awhile. That's pretty radical bump stick. I found it to be too much cam for a street car, but your results may vary. Now I 'm pulling these numbers out of a 40 year old memory, but .017 intake and .020 exhaust is how I remember it. Call Ed Iskenderian, he's still in the office or the shop every day last I heard. He'll tell you right. The Hardface overlay was an option if I remember right.
If I remember right , hard face overlays are short life cams and do not like low speed driving and are not recommended for the street. Check with Isky....
The Jalopy Journal
