Will changing the pump assembly on a mechanical 110 GPH fuel pump increase the GPH on a stock marine 330 HP fuel pump? Cant find a marine 110 GPH pump that will bolt to the sea pump.

Order any 6 bolt pump, like the jegs 170 gph, and use the bottom half of that, your original top half

CV - Everything Racing - CV Products

The holley pump I have is a 6 bolt. My question I have is by just changing the pump assembly will it make my stock pump into a 110 GPH?

why do you think you need more on a stock 330 ? you could buy a merc one for a 525sc now it is over $500

I have a 625 hp 548ci. how many GPH does a stock pump have?

Yes. It's a common mod to do. The bad news is 110 is inadequate for that kind of power. On paper it may spec out, but not really in practical application. I'd use the 130gph Holley pump with a bypass regulator set up. Fwiw the 3/8" line from the tank proved anemic for my 500hp.

I was running a 110GHP electric with 8an hose, 6000rph still kept close to 6 lbs.