Does anyone know the diameter of the front sway bar?

You want to know the diameter of what you have? Check with a caliper?

 

24mm

 

A cheap one is maybe $5~10, more than adequate for rough measure like round bar OD. Or get a decent dial gauge style for $40~50, you won’t regret it. Avoid digital; they CAN eat batteries. The high end ones might be ok, but who knows.

 

they W I L L eat batteries /

 

There is a formula, which I don't know, where you can wrap a piece of paper around it, mark it,
then measure the length of it and apply the formula to get the circumference.
You could also us a cresent wrench over it, tighten it and then measure the gap.

 

Divide measured length (circumference) by 3.14159 (roughly Pi) will give you diameter.