So my bilge pump went bad, pulled it out the other day, its a Rule 1500gph, does this sound about right for a 86 wellcraft?

do you think a 1250 will get the job done?

My thoughts are always you can never have too big of a bilge pump. I also added a second one to the boat and wired to the 2nd battery, the whole once of prevention.

I once hit a plastic bag, shut water flow off at speed, overheated badly super quickly and melted the exhaust hoses, next fun fact was that lower exhaust hose that connects downtube to the "Y" pipe is under waterline. Took a lot of water in fast and both pumps pumped it out and kept boat floating while TowBoat was on their way. Pumps are cheap IMHO.

I think if you're taking on 1250 or 1500 Gallons of water Per Hour, you've got other things to worry about

The 1250 should be fine.

I allways run 2. Never can be too safe in that department.

Just remember, they are rated pumping water horizontally, they don't pump nearly as much when they have to lift the water two or three feet. Get the biggest you can afford. You'll forget about the cost savings when your boat goes down.