The 780 Holley can be jetted & set up to work bitchen with a Cleveland. Any carburetor needing a rebuild, or that is not set up properly for the application, shall possibly create all sorts of engine performance issues.
Double pumpers provide crisper acceleration at the expense of worse fuel economy.
My experience with standard displacement Clevelands has been that day in and day out, from mild to wild, the 750 Holley can fill the bill. For example, I quoted the specs for Rich Poulos' Pantera the other evening, which includes a 600 bhp at 7300 rpm 385 cubic inch Cleveland, equipped with a 750 Holley.
At least one reputable engine builder within the Pantera hobby has a preference for the 700 Holley. Many relatively stock engined Panteras are equipped with the Edelbrock Performer intake and a 600 Holley for an improvement in throttle response. However that small carburetor results in the motor loosing wind at about 5500 rpm.
Keep in mind, when comparing Barry Grant (Demon) carburetors to Holley carburetors, that each manufacturer measures the flow capacity of the carburetor differently, resulting in about a 100 cfm difference for carburetors of the same size, i.e.
700 Holley = 600 BG Demon
Not enough intake manifold vacuum? The situation can be improved by setting the distributor properly. Intake manifold vacuum is NOT the vacuum signal that oprates the secondaries on your Holley carb by the way.
How much bhp is lost by too much valve clearance? Kinda depends upon how much excess valve clearance we're writing about. Enough that you will feel the difference in the seat of the pants once the clearance is set properly.
cowboy from hell
