Grinding noise above 2800 rpm

[Gerry Djerrahian <jiradi@domain.elided>]

Hello everyone,
My name is Gerry and I have just joined the Stag Digest, introduced to
me by Tim Buja.
I live in Montreal, Canada and I have a 73 Stag which I bought from
Florida in May 97.
Having restored the body and interior (which took longer than expected
including several mishaps), and thinking that I was finally going to
enjoy the car before storing it for the winter, I began to have a
terrible grrrrr sound that comes up when accelerating after 2800rpm. It
sounds almost like the torque converter and only begins when the oil
comes to operating temperature. I have changed the oil to a thicker
20W50 with Slick 50 but this has not helped. I suspect con-rod bearings
but am hesitating to take the lower-end apart. My oil pressure gauge
shows 45-55 psi when cold, and 25-45 when hot.
The jack shaft and water-pump are new including timing chains and
tensioners. I did have an unfortunate incident as I was driving to the
body shop last year where the water-pump gears got stripped. The engine
did overheat briefly. The heads are OK. I don't burn oil.  It never
overheats. I have no coolant leaks and the water temp gauge never goes
above 3/8
...and yes I have a new thermostat.
Tim Buja's first suggestion was to check the fan coupling and he was
right as mine was seized completely. Having changed it however, I am
still plagued with the same problem as that noise is still there above
2800rpm! The car is a lot faster and the motor seems to be turning over
more comfortably.
My gut feeling tells me it could be the torque converter because the
grrr sound comes
from that direction. Unfortunately, I don't know enough about it! Could
that be possible?

To inspect for any bearing wear, I was thinking of removing the
cross-member and oil pan  but I am told by Rimmer in England that it is
easier to remove the engine!?! Is that true?
Do I have any other choice but to take the engine out and strip it?
Obviously the crankshaft will need to be ground and hardened. What are
the limitations?

I also need to change the shocks all around including new poly bushings
to improve the handling. Any suggestions? Rimmer has the Spax gas shocks
which are uprated and reasonably priced.

Happy New Year to All!

Gerry Djerrahian