What the heck is going on here?

[ray_mcavoy]

Hi Spassmacher,

That looks like the stock bypass hose/adapter setup that was used on many 60's truck 327's. The pickup truck applications like yours used one bypass hose. While the medium duty truck applications used two hoses.

If you want to keep the stock bypass setup, the parts you need are still available. I recently went through tracking them down for the 327 we're getting ready to put in dad's 66.

The correct moulded rubber hose is Gates #20566. It's available from www.rockauto.com if you can't get it at a local auto parts store.

The 90 deg fitting that screws into the top of the water pump was a bit harder to locate. The original has a 1" hose barb and 1/2" NPT threads and is used in conjunction with a 3/4" to 1/2" reducer bushing in the water pump. The closest thing I could find were these fittings on ebay --> http://www.ebay.com/itm/5-FITTING-HO..._Parts&vxp=mtr They're nearly identical to the original except they have 3/4" pipe threads that go directly into the water pump (eliminating the need for the reducer bushing).

Originally Posted by Lee H

It was a safety precaution in case the thermostat stuck closed.

I've also heard that the bypass helps prevent localized hot spots inside the engine by allowing a small amount of coolant circulation while the engine is warming up with the thermostat still closed.