Denis, just be aware that most car headers aren't going to work with most dyno set-ups. Guess how I know. At any rate, after going through the same thing that you are (re. the lack of FE anything out there in the world of the small block chebby) I wound up using my Cobra's headers to get the job done. Definitely not optimum for the job but it's also what I have in the car, so............
You may have to get a set of old headers then cut and re-angle the head tubes to clear the under engine area where it'll be attached to the dyno cart.
This is mine on a DTS dyno.
