If you're not familar with Holley's I suggest you buy Jeff Williams book on rebuilding Holley carbs.You can find it on Half.Com for less than 10 bucks.Then read the book well and rebuild the carb yourself.Holleys are very easy to work on, it all comes apart and you can really see what's going on.Almost all Holley problems come from the last guy who worked it.Out of the box a Holley will perform well on any engine within the carbs limits.Any stock 390 Holley should start up and run ok on any mild street engine, no matter the number of cylinders, it may have flat spots and need tuning if it's the wrong model , but it won't have the symptoms you describe.I'm assuming you sprayed carb cleaner or something similar around the carb base and intake manifold to head area while the engine was running to check for leaks.So your carb adjustments or interal adjustments are way off.
