cooling system washer

when you replace your thermostat with a washer on a SBC what size hole do you put in the center for it to run at about 175o?.I'm going to make my own out of brass stock at work & also need do know the outside diameter.(don't have a thermo here)
Thanks
jimV

 

<font color="green">O.D. is 2.125" and I don't know about the I.D. you would need. Must be alot od variables there.

I've heard of people doing this on roundies but it doesn't seem practical for a driver.

Why not just run the thermostat?

RASHY </font>

 

<font color="green">The thickness of the thermostat at the flange is .049/+- by the way.

RASHY </font>

 

My dad told me an extra pair of front wheel bearing washers was the right size to fit into the radiator upper hoses and the hole ID was the right size for the restriction.
The washers sat right on top of the outlets and the hose kept it in place.

He used to crew for a flathead midget racer and that's what they did.
I'd guess the washers would work for the later flatheads as well.

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Now that I looked at your post again I see it's for an SBC.
It's going to take a lot of experimentation to set up a restriction washer for a particular temp.
Not to mention the load on a street vehicle is constantly changing.

Do yourself a favor and get a quality thermostat and let it do the regulating.