This is actually for the TBI intake on my truck, but I need to find a hose fitting that fits into the port in the rear intake coolant passage. I broke the stock hard line that went there recently when I had the intake off. It's getting cold outside, and I need to hook my heater back up. Anyone know what size/thread it is?

 

Nevermind, I found it on another forum. Looks like it's 1/2" NPT in case anyone's curious.

 

Tip: when you replace the fitting that supplies the heater core, make sure you restrict its flow somehow. If you just put a hosebarb fitting on there, excessive ammounts of coolant will bypass the radiator at idle, causing overheating. On the few cars that Ive had to replace them, I usually fill the inside of teh fitting up with lead to form a plug, and drill an orafice thru the center of the plug. If you look inside the stock fitting, you should be able to see a restrictor in there of some sort. Try to match that so everything will still work properly.

 

Yeah, I was thinking about that. I think I'm gonna re-plumb the heater the right way - one hose coming out of the intake to the core, and the other from the core to the inlet on the radiator. That way coolant can't bypass the radiator via the heater hoses. I'll need to plug off the fitting in the water pump though, any ideas what size thread it is?

 

Almost all fittings on a SBC are the same, the one on the water pump included. -1/2" NPT. (if they're not that then they'er 3/8NPT like on the heads)

I finally got around to hooking up my heater core, I feed it from the passenger head port using a 3/8 NPT to 5/8 barb 90* fitting with only a 1/4 I.D to restrict it and returning into the water pump. Works great and blows warm air in 1/2 the time it takes my other truck that is feed from the intake port and no over heating, other than me heater I dont have a bypass though, if I did I would restrict the heater even more than that.