help me identify these heads

OK Loungers,

Before I accept my defeat and ask it on FB, I want to try it here first :-)

I've had these heads several years now and I just want to know if anyone recognizes the work. The guy I got them from got them out of a big batch of 70s-80s high performance parts that he bought true auction here in Belgium, but the shop it originally came from was US based. He didn't have a clue what shop and why it was auctioned. He bought the parts somewhere around 5 - 10 years ago, nobody knows how long they have been in Europe prior to that.
they are (old?) MOFOCO 041 castings, rather rough around the edges still. exhaust seats are for 40*35.5
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the inlet ports are enlarged allot, so much both ports touch, not sure if this is going to be usable as such. They used Defcon or Belzona to work around the thin walls, there is a little spot of Defcon/Belzona visible on the inlet itself
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Exhaust port at the flange is only ~30mm (~1 1/16"), so I want to believe they were never finished. they did shave the valve guide flush

they have a serial number on the exhaust flange: 296634 and have some stamping next to the combustion chamber (5 of S)
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There also is a 4 (or IIII) next to a combustion chamber, I think to link it to cylinder 4. but nothing much more to see.

Does anyone recognize the work done?

Thank you,
Glauco