[3macs1]

Steve:
I always thought so also but there seems to be a gray area when they took a finished 2 bolt and converted it on the fly to 4 bolt. Those I could see them not bothering with the oil mods.
Another thing that makes me believe this is true is I had that engine for years and would have noticed the plugs especially when I was racing l-72's.
Let us know what you discover
Joe