Have a bad bearing noise in the supercharger of my Riviera, how hard is this and can it be bypassed without replacing the supercharger?

This will totally depend on which generation of engine is fitted. If yours is the older engine that has the M62 as standard the answer is No. The M90 is physically bigger than the M62 so it won't fit past the injectors, they are mounted higher on the older engines. The intake port layout is different requiring a 'custom built' replacement manifold. The drive belt routing is also totally different. Read this old thread, (from 2007), it mentions the fitting issues this upgrade can have.
The newer engines were heavily modified to allow for the bigger, more powerful M90.
https://rivperformance.editboard.com/t4338-faq-m90-blower-in-place-of-m62

First off............. It sounds horrible. The bearings are the primary failure point. The supercharger is actually not that prone to failure. I've had several SC 3800's with well over 150,000 miles without an issue. I've lost idler pulleys many times but an actual component failure like the SC./

that's funny I have the same problem kinda. my supercharger broke and now my battery keeps dying. I would replace the battery and get all the wiring back there checked out. are you interested in selling the supercharger?? email me at [email protected] I can give you a brand new battery, brand new terminals and some cash. 10.24.13

Not sure what the problem is hear, it knocks, well if it is full of oil and the oil is the correct type then the supercharger is defective would be my guess. Since that is a guess have a local dealer confirm the SC is the noise. It could be lower engine noise as well don't you think?.

Faster and safer to drop the whole unit from the bottom with the cradle. Replace the supercharger snout bearing and seal before you install the replacement engine and the supercharger belt. Also replace the boost valve to your transmission just to ensure your getting the proper transmission line pressure throughout your transmission.
Thank you for using fixya and be safe

Yes. Does the supercharger belt run anything else? I can't remember.

1995 riviera is not turbocharged; it is supercharged--big diff; if the noise sounds like rocks tumbling, then you need to replace the plastic coupler in the supercharger; part is cheap -;labor is a lil high; it is a pain because you have to remove the alternator bracket on the buick version of the 3.8

THE ENGINE WILL BOLT RIGHT UP. YOUR PROBLEM WILL BE THE ELECTRONICS, SENSORS, ECM PROGRAM, ETC. WHY NOT PUT THE SUPERCHARGER ON THE NEW ENGINE? IT SHOULD BOLT UP. MORE POWER IS BETTER AND YOUR MILEAGE SHOULD BE AROUND 30MPG.

You can replace the nose with bearing. If its making a clunking sound you will need the whole unit. Check out some of the people that rebuild these for more info.

you can not put a regular 3800 intake in place of the 3800 super charged engine,the compression ratio is lower than the regular 3800 engine.......!