I am working on a buddy's Chevelle and somebody put a Double pumper on it... Its a mild 454 with a TH400 and a "stock" stall converter with mild gears (haven't checked, but probably 3.31 to 3.55s).

I am pulling the carb off to detail the engine and was wondering about istalling one of those Holley Powervalve protection checkvalves...

Do I have to disassemble the whole carb? Or can I just pull it off the intake, install the valve and reinstall? I really don't want to get into rebuilding the carb, but figured the protection would be nice, especially with the mismatched carb...

You have to take off the throttle plate.... not too difficult or invasive really.