At the G2G here in Marin County yesterday as usual at these things we were popping our hoods and mulling things over. We found a 1979 300D that does not have a Vacuum Control Valve [ VCV ].
My research has been to try and find a 617 engine for another year that does not have a VCV.

Can anyone shed any light on this question? Could this be a 617 from a 115 chassis?

Chassis...... Engine... Model.... Years Mfgd
115.114..... 617.910...300D..... 1975-76
123.130..... 617.912...300D..... 1977-81
116.120..... 617.950...300SD... 1978-80
123.133..... 617.952...300D..... 1982-85
126.120..... 617.951...300SD... 1981-85

Regards,