I have never seen any factory heads with dual drilled intake bolt holes. I think what you have there are either aftermarket castings or modified factory castings.
I remember way back when a member here made a jig he would loan out to drill the heads intake bolt pattern. Never seen or heard of a dual pattern from the factory.
These came off a van sitting in a junk yard back in early 2000s.
No way my memory gonna recall the specifics. lol
It looked 100% factory.
318 came with roller camshaft about 2 years before 360 started to get em.
Pretty sure I read on here a couple decades ago that during crossover the factory drilled the heads with both patterns.
