Putting an 81-82 into a 85. Everything is going fine except I noticed that the coolant outlet off the side of the rear cover below the oil cooler is only a straight 5/8" nipple and does not have the tee nipple as my 85 did for the heater hose. But there is however a 3/8" nipple that comes straight out of the top of the block right below the heater outlet from the firewall. Is this where the earlier cars supplied the heater coolant? Whould it be better to just hook up a tie fitting to the one on the side of the block and plug off the 3/8" nipple or get an adapter and hook up the 3/8"to the 5/8" inlet on the firewall? I had thought about just threading the 3/8 and capping it.
Thanks

 

when I had a S1 (1979-80) engine in my S3 (1984) we just used a T. I guess it'd be a better idea just to drop the oil-to-water-cooler for a oil-to-air one though.