[Gearhead999]

You take off the float bowl and the plate that hold the two jets. The power valve is screwed in that plate from the carb side. If you want to be certain that the valve is blown. When you take the carb off the engine don't tilt it and dump all the fuel out. Keep the carb upright and drain and remove the fuel bowl. The fuel will drain out when you take a bottom screw out of the bowl. [four screws hold bowl on] Then pry the jet plate off. When you see the cavity that the power valve fits in to, look for fuel here. If you have fuel there the valve is blown. Plus, if you have gone this far you might as well change it anyway. Good starting, normal run of the mill power valve is a 6.5. Get new gaskets too. They are a pain to scrape but someone has to do it.

Put back together and run it. Bet it runs better. You shouldn't let it backfire if at all possible. That's what ruins power valves.

They make a little pop off valve kit that you can install in you carb to HELP protect the powervalve from backfire. The kit is REAL CHEAP and easy to install. Check it out while you have carb off car.

Happy Thanksgiving, let me know if you need help.