Don;
I noticed the same problem when I switched a '65 413 into my '65 New Yorker. I
had to go back and change the oil pan to one that would allow a full range of
motion for the idler arm. Couldn't figure out why it didn't want to turn very
sharp to the right 'til I looked underneath at the dimple that the idler arm
was trying to make in the oil pan.....
Of course, having to grind the block for the different engine mounts was a
treat, too. I only found that out after I had assembled and painted the engine
prior to installing it.
Cheers,
Roger