My rebuilt engine didn't have a oil slinger. I had an opportunity to replace the camshaft (its a long story) anyway, I noticed the front seal had been leaking. While putting the engine back together the manual mentioned an oil slinger. So I did a little research and found out Ford had done away with the oil slinger but some guys on Ford Enthusiast Forum mentioned they had put an oil slinger in when their rebuild didn't originally have one and it helps keep the oil seal from leaking. This oil slinger fit right on the crankshaft. Terrific price and received it quickly. Thanks!