The 4.5 and 3.5 fit without issues, it's possible a 116 chassis A/C setup was used but I know from pulling one from the yard, aside from a casting change, the A/C idler for a 116 4.5 circa 1975 was identical to my 72's 4.5. To keep things simple, MB used the same mounts, setups, etc for all 116 and 117 engines since the blocks were NEARLY identical.

Which brings me to this: Is the front of the vehicle jacked up with the wheels down when you started it? When I did this with mine I had the same issue. The engine does not like being run with both front wheels dangling from it, with the sway bar and subframe geometry.

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Current:
2021 Charger Scat Pack Widebody "Sinabee"
2018 Durango R/T

Previous:
1972 280SE 4.5
2014 Jeep Grand Cherokee Limited "Hefe", 1992 Jeep Cherokee Laredo "Jeepy", 2006 Charger R/T "Hemi"
1999 Chrysler 300M - RIP @ 221k