Hmm well i really did. I did because when i called holley about doing this they say point blank that they had no idea if it would work on a BG/ demon car and click end of discussion. so i was vary careful with matching the demon gasket with the gasket that came with proform. no differance. In fact the only thing that that i notes was when i replaced the main venture. the proform didn't have the power valve drilled out for the secondaries power valve. that main body/venturis can be bolted on either way but the power valve would Not work if you put it on wrong. the demon didn't matter which way you installed it. Not saying your wrong and sure could have overlooked something as well. Thanks for your response.