Originally Posted by an8sec70cuda
The 1/8" pipe plug is factory and I believe to be only on motorhome heads. I just sold a set like that a few weeks ago. I removed them from a 440 that came out of a motorhome.


Starting to sound like these are some type of motorhome heads. The 452 heads I used on my 440 doesn’t have that boss drilled and tapped. It also took flat/gasket spark plugs

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Last edited by metallicareload; 03/29/24 12:07 PM.
440, 4-Speed, 3.54
1968, when Dinosaurs ruled the Earth