[Jac Mac]

Rick,

Given that this type of thermostat was meant for low pressure ( or even no pressure! ) cooling systems its unlikely that they would be available in higher temp range.

In your case I think it would pay to make or have made a specific thermostat/ by-pass housing that can be fitted in the top hose/s. You might be able to do it by bolting two themostat housings back to back. Some SBC have a sender unit fitting cast integral that could serve as the by-pass if the t/stat bulb can be accomodated without causing too much restriction.

Jac Mac