Only if it were made to work with a Thermoquad. They are spread bore and most spacers are square bore. As far as what type/size spacer you run it depends on the application and what your trying to achieve.
Okay, I thought I would go with a spreadbore. I will be running a mild 340, a rebuilt 904 and an 8 1/4 with 3.55s. Its gonna mostly be a street/track car as I am really close to Road Atlanta. I am gonna be aiming at 400hp, maybe a little more.