I think you mean a 3.8 as GM doesn't make a 3.9, you need 5 qts. of oil with a new filter.
Drain all the oil out into a clean container and then put the correct amount back in. Do not overfill. Overfull is just as bad as not enough oil.
No
Yes
just an inch or two
The most economical and practical solution would be to buy an SS Monte Carlo with a V8 already installed.
drop the oil pan and put in new screen and filter then put the pan the same way you took it off
It is the same car!
Of course not
Yes.
Yes
they can be installed on any veichals
1 or 2 inch lift