Noisy??? only when the fan clutch kicks in and that lasts all of about 1-2 minutes before the engine bay is cooled. On a long hot days drive mine will kick in maybe 3-6 times only. How hard are you pushing your rig?
Keep it at 2,400 rpms and you will be just fine. As far as the exhaust manifold issue, let it idle for five minutes prior to shutting it down and you won't have an issue.
Sometimes we make our own problems (not saying you do) but if you put your foot into the radiator, charge up every slope, then slam into a gas station and shut down the engine and run inside, then I guess you can expect issues. If you take care of the 460, it will take care of you.
When I read some of your older posts about your rig, I wonder if you're not overthinking some of this.
"I BOUGHT my 96 Pace Arrow for 7500.00....burnt and blistered by the sun sitting on a texas ranch. Absolutely beautiful inside...48000 mi.. and all the paperwork including the new window sticker...$88,000.
I have done..new yoko tires, new in tank fuel pump,batteries, oil/filters and all that stuff....new carpet,ex manifolds and new dual exhaust,sway bar bushings, Iam very happy with it...still want it to make me trust it.....Yes...mech. inclined is a curse ....I knew all this when I bought it. Iam getting ready to repaint it. But this is what I do...so no big deal unless it leaves me dead in traffic. I know when Iam finished I DID IT, and I trust my work, and don't have to worry about some other persons Joe McGee work."
"My fear is a stalled MH and toad.....in traffic in town .....A BIG FEAR !!
I have had flats on the duals...lucky to have been close by to repair.
No way can I change a tire on my MH....and you cannot drive far with one on the rear without damaging the other. All I carry is a NEW spare....
This is why I drive and test after a long sit.....even tho I start every week and drive around the block every mo.
I do a lot of preventive maintenance.
To be honest I wish I had my 88 Allegro 454 with carb and no computer back . So much simpler."