1966 327 Upper Radiator Hose Question

[Ronald]

Hi folks,

I would like to replace my upper radiator hose. I have a 1966 327 cu in, 300HP motor. I have a stock aluminum manifold (which I think was for a 350HP motor). I have the stock DeWitts aluminum radiator.

I see there are 2 hoses available for a 66. For the 300 HP it calls for a hose called: Radiator Hose Upper 327 Except Special High Performance (GM Part # 3887154 ). I think that is the one I should get.

However, there is also a GM # 3887156 which is for the 350 HP motor. That one is called "Upper 327 Special High Performance".

So... my question is what is the difference between the two hoses and how do I determine what hose I should get?

 

[Tom Bryant]

66 300 horse thermostat housing
66 350 horse thermostat housing

There were two different thermostat housings used depending on the intake manifold; iron or aluminum. They point out at different angles. See above links. If your 350 horse intake has the 350 horse thermostat housing, then use the high performance upper hose. If not, you may want to get the correct thermostat housing to match your intake just so everything fits as it's supposed to. The thermostat housing mounting flange on the intake is 90 degrees to the fore and aft line of the iron manifold and points more towards the driver side about 30 degrees on the aluminum manifold.

Tom

 

[Ronald]

Thanks a lot Tom, that is most helpful. I have the 300HP housing. If I don't change the housing, would the hose for the 300 HP work (GM Part # 3887154)?

Ron

 

[Tom Bryant]

That housing is used on many small blocks but isn't the same as the 66 327/300 housing in the link above. It points up at a greater angle, but it would be close to the right angle for the 300 horse hose as mounted on the aluminum intake. I can't say for sure but it will be close. It should be long enough. It will just be up closer to the hood . If the one that's on there now clears you should be ok.

Tom

 

[Ronald]

Great. I'll give that a go. Thanks again.