I bought a 69 chevelle without an engine. Prior to my ownership it had a 427. I am working with a 454 long block now. This is my first build. I need to know whether to buy a long or short water pump? Any other cooling concerns? I am also considering a Speed Demon 750 vacuum carb on a stock Q-Jet manifold with an adapter and a 1/2 inch phenolic spacer. Is this a decent setup for 425-450 HP? The engine has 049 heads, 10:1 compression, a mild cam, and the car came with headers.

Long water pump. SD 750 should be fine....

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Rick

long water pump, it makes your belt package more compact and the brackets are more rigid to help keep from throwing belts. The 750 speed demon is fine for your motor but I would ditch the stock manifold and get a performer rpm or air gap setup.

A short pump would give you more room in front for a fan or other stuff. That is more of an issue in 64-67 cars.

Holley used to make a spreadbore carburetor, not sure if they do or not. I don't like the idea of using adapters, just another place for a vacuum leak. I do run a phenolic 4 hole spacer for the time being, going to try an open spacer at a later date.