Rusty, perhaps I wasn't clear in my previous comment. What I'm talking about is the coolant drain plug threaded into the right rear of the engine block of my 1974 slant six motor. Currently, I have a plug with a hex (Allen wrench) fitting on it. I'll shortly be removing and painting the engine and I'd like to replace this coolant drain plug with a plug that has a square head. A square head would be very easy to remove when doing coolant changes, as all I'd need is a crescent wrench or an open end box wrench. So I bought this plug and am wondering if this is the correct one for my engine. The one currently installed in the engine looks to be 3/8", but until I get it out of the motor I won't be able to tell what size it is. Do you think I bought the correct plug?
