The Derale 15" Heavy-Duty, Stainless Steel Flex Fan, Chrome Hub - Belt Driven # D17215 is designed to be a universal replacement for a variety of vehicles, so you'll just need to know the size of your current fan to determine if this will fit. As long as you've got a 15" diameter belt driven fan on your 1973 Cutlass with the 5.7L engine then this will work for you.
If you find that you've got a different size belt driven fan on your Cutlass just let me know and I can help you locate an... view full answer...
I'm not sure how your 1986 Oldsmobile Cutlass is setup but the Derale 40/60-Amp Dual Relay Wiring Harness for Dual Fan Assembly # D16765 that you referenced is a great option if your electric fans, including one on a remote, fan-mounted cooler, draw more than 10 amps of power. These help to protect the electrical system on your vehicle. view full answer...