The best think you can do is redo your transom and stringers to use either a late model Mercruiser motor and drive, or a late model Volvo Penta motor and drive.
This will require replacing the transom
1990 or older motors used a 2-piece rear main seal.
In 1990 the 3.0 was redesigned to use the same rod and piston in the 5.7 (for parts commonality) and the crank seal was redesigned to a 1-piece.
Most of the trucks I pulled apart have a windage tray.
Windage tray is very important on sustained high-speed motors
Even the front drive motors have windage trays
Why are you replacing the pump in the first place?
Was your pump leaking, or pushing fuel thru the tygon hose? If not are you replacing the pump just for the sake of replacing the pump?
The stock pump is a Carter marine pump. About $50 at places like Summit racing or Jegs. Do not buy any pump...
What is your budget?
Your boat came with a 1992-1995 5.7 liter.
However a 1996-2013 5.7 will bolt right in
Your current motor most likely has bad exhaust manifold, so you have to replace them
The front accessories are probably good
I personally would look for a low mileage 1996-2000 5.7...
Your boat needs a full restoration.
Last thing to rot is the floor. Decades after the stringers and transom
Read link 14 in its entirety, then the other links
https://forums.iboats.com/threads/how-tos-and-other-great-information.283508/
The center console just sits in a divot in the floor on the pioneer. The caulk is 95% cosmetic to keep crud from growing in the crack
It should still be UV stable life-caulk. https://www.boatlife.com/product/life-calk-cartridge/
