Hi Guy and Girls I have a under-drive pulley on my 400 olds
The problem is running hot around town in stop and go traffic
I know it should be a bigger crank pulley but I can't find one yet
Anyway A Friend told me take the thermostat out replace it with a washer than
plug the by pass outlets What do you guys think?
Its fine around moving speeds w/ac going
Any help the water pump is 6" snout I have the room for a 6" crank triple pulley hard to fine I bought a complete undrive kit from mondello a few years back because I couldn't find the right pulleys Thanks Steve

 

Waterwetter does well, but if it's overheating now you will need to get a finger on it before the temps get into the 90's. Electric fan(s), 160* thermostat, larger radiator, a good factory six blade fan, etc are things you could try. I wouldn't recommend removing the thermostat because you will have little heat blowing out of the vents and it's still winter. Do you have a shroud?

 

What temp does it get to?

 

220-230 Then it runs like crap

 

Let's back up. These cars did not overheat when new (with stock pulley ratios). If you have a clutch fan, the underdrive pulley isn't really providing much in the way of HP improvement. Ditch it, go back to stock, solve your heating problems. Unless this is a dedicated race car where you need every few hundreths of a second, the underdrive pulley isn't doing anything for you.

 

It has a clutch fan I can't find what I need for crank pulley
Steve