any one know if a 1998 454 mag has a port for a manual fuel pump

no, they have it on the sea water pump ! Its a gen V block.

not if original block..Gen VI

No.
You have to run a Sea Pump with the attached fuel pump.

I have a serpintine belt system all the pumps with the fuel pump add on are v belts. what then

Well simply go and buy an electric fuel pump. Very easy install. You can buy them from a decent perf store or summit. Pull old one off plumb new one in and go. Make sure you get one for fuel injection psi needs.

I have a Gen VI 454 block (built in Feb 99) sitting in my garage that has the mounting boss and provisions for a mechanical pump. However, you also need to make sure the cam in your engine has a fuel pump lobe on it.

If your engine is a Gen V, then yes, it will NOT have provisions on the block for a mechanical pump.

You can tell the difference by looking at the timing cover. Gen V has the standard stamped steel cover like on the old Mk IV, while Gen VI has an aluminum 6-bolt cover. You can also get the casting number off the back of the block above the coupler housing to determine whether it's a V or a VI.