ktmp

I've just installed an LS1 into a 280z. I'm using a Ron Davis radiator. The upper coolant outlet on the radiator is standard but the lower outlet on the radiator takes a 1" NPT fitting. There are several options that I can go to get the NPT fitting to the correct hose size to connect to the LS1 water pump. My question is, is the 1" diameter too small for adequate coolant flow? Also, anyone seen this on a radiator before? I've had this radiator for a while, picked it up at a swap meet. Please let me know. thanks

Old Geezer

iTrader: (3)

Yes, it's too small. Needs to match the t'stat neck, or the pump may cavitate.
Sounds like you have a Davis race radiator. The correct OD for the lower hose is 1.5".