1980 SN drivetrain noise

First off, great forum you guys have here. It's clear there's some knowledgeable folks on the site. I've got a new-to-me 1980 SN, 351 PCM. When going straight, drivetrain is silent. However, when turning either port or starboard, there is a significant noise. It is not a squeal like metal grinding on metal. It is a groan like the drivetrain is straining. The harder/tighter I turn, the louder the groan. I do not feel any vibration from the drivers seat but I also haven't ridden in the back.

I am certainly not new to boating but this is my first inboard so I am not sure if this is normal operation or whether I need to be concerned. My first guess is strut bearing but again not sure if this is normal. Previous owner (my uncle) says strut bearing has been replaced but he doesn't remember when. Appreciate the thoughts! Thanks guys.

The noise could be normal, but hard to tell what the intensity is by a text description.

If you haven't already, I would check alignment (should be within .003 ") of the prop shaft to tranny,
Also check the strut bearing (shouldn't be any discernable play).

Another possibility is weakened stringers. If weak from wood rot, they could be allowing the engine to move during a turn.   

You can check their health by tapping with a hammer, should have a solid sound.   Also check lag bolts to see if they are holding torque.

Tim is correct on the cradle vs stringer issue. My 80 makes a Squeal type noise with harder turns in either direction and shaft is perfect.

Hello all,
I have also a late 1980 hull,maybe it is finished in 81. With a 351 ford commander. Can anyone tell me what a cradle is? And the function of it?

Greetings roy from the Netherlands