Does anyone make a mechancial fuel pump that mounts on the sea pump housing that has 1/2" fittings?

I'm not sure, but I don't think so. I believe that pump is not interchangeable with any other BBC pump. And I have never seen an optional one offered by Mercury Racing. If your looking for a major flow increase, you may have to go with a quality electric pump.

cp offers upgrade for merc pump no others available cp pump good for about 600-650n/a depends on fuel lines

Yup, Hardin Marine had one on display at the Key West vendor area

CV products offers a billet fuel pump that fits the merc seawater pump. It will handle at least 700hp. It is expensive, but it is the best pump available, and is rebuildable for under 100 bucks when the time comes.

Don't spend a lot of $$$ on a speacialty pump if the armature part of the sea pump mounted pump is in good shape!
Any high volume Holley or Carter with the 6 hole pattern will interchange the diaphram housing and rotate to any position you desire.
I promise!! I use these pumps to force feed the high pressure pumps on EFI blower motors.

Dave

I have used the carter on a couple of motors and worked great.

Thanks for the reply's. What I have now is the stock merc pumps which are good, but I think I am going to need more volume for my 625hp motors. That is why I want to switch to the larger 1/2" fuel line.
Thanks again,
Greg

Looking at the seawater pump mounted fuel pump, can someone explain how to remove the arm off the old pump and the diaphram. I have several new engine mounted Merc pumps and hate to drop $160/ea for 2 new pumps.

What you do is unscrew the approximate 6 or 8 screws on the lower half of the pump. Seperate the two pieces, and switch them.
I bought the Keith Eikert pumps and they were only the lower half's, but had the larger 1/2" ports. I have been very happy with them.