I put a edelbrock 600 cfm with mechanical secondaries on my 477.It came from the factory with a holley that had vaccume secondaries.Will the edelbrock dump in to much fuel because the secondaries are forced open?The engine is running really rich,blowing flames out the exhaust and running really bad.Is it better to have vaccume secondaries on this particular engine?
Depends on application. If you are racing this thing only, then mechanical are the way to go. Street use usually goes with the vacuum secondaries. What is your timing/cam setup? Seems like it's gotta be more than just richness to blow flames out the exhaust.