I have a one owner with an LS-5 and a 4 speed. It also has Factory A/C. For the last FIFTY YEARS with the factory VO-1 cooling system. NO issues so far!
SO,,, When I built my / Driver//Cruiser (1970 Nomad Wgn.) I stuffed a 468 in it and a 700R4. I went back to the 1970 Chevrolet VO-1 Cooling system, WHY? Its easy, My LS-5 / M-22 car has been just fine for fifty years. YES,,, A lot of " NEW and IMPROVED " items on the table to work with.
My Silverado has TWO Electric fans, They are wonderful. My Silverados engine bay was designed and has the proper ductwork for the fans. NOTE: Both of my 70s ( 454 & 468 ) have the 1970 style VO-1 cooling system, With EVERY PART & PIECE in place! ( NO after market ANYTHING in my cooling system) ALL parts O.E.M.-Pulleys,,772-fan blade,,clutch,,811 pump,,shroud,, 4 row Cop/Brass,,ALL the rubber pieces.
I can park my 1970 468 driver in the sun on a hot day, Turn on the converted factory A/C to ( R-134) and let it sit and idle untill its out of fuel and does not get hot and boil over.
A mechanical or an electric system will KOOL your chevelle "" IF "" It is DESIGNED for your car.
When you get old like me you figure it out... " Good parts aint CHEAP, AND Cheap parts aint good."
Do what makes you happy!