I recently repowed the boat from gen 5 to gen 6 big blocks. My question is becasue I have a different crank balancer I had to buy a new crank pulley. The pulley had a larger diameter puller for the sea pump. That being said this will make the sea pump spin faster. Can anyone see any harm in doing this? I am kind of worried at high rpm that it may not be able to suck enough water from stock Bravo pickup? went from 4 inch diameter to 6 inch diameter pulley. Any input from experts? Also anyone know where I can get a BBC waterpump that will host a 8.5 inch crank fluid balancer. Stock waterpump will not fit. I know L88 corvette 427 big block waterpump from the 1960's will work but do I have another choice if anyone knows?

I believe at high RPM, high boat speed, the sea pump itself is getting alot of help from "force" feeding from the drive/pickup. The pump itself probably works harder pumping at idle than it does at high speed.

As for your circulating pump issue, I cant be of help. You can always eliminate it and run a crossover setup if all else fails.

I do have a set of crank driven waterpumps and crossover shafts. Maybe it would be easier to run it that way. Thanks for the heads up.

The sea pump is all you need.

I have a crossover setup with the stainless steel seawater pump and highly recommend it, engine runs right at thermostat temp.

How are you guys routing your hoses from sea pump using crossovers? I may just take this route as it is a much cleaner look.