Ball valves will not restrict your flow enough to matter if open all the way through, just a bit of piping loss, not enough to matter.

If the intakes are low enough and along the center stringer, could you just solid plumb them several feet further along and put the valves near the front of the engine? Either that or the metal rods connected to the handles works nice also.

You could always go with electric ball valves. Pricey for a 1" NPT if I remember compared to a standard ball valve, but they flow the same and have power opening and closing. Really guessing, but I think the price was in the $400 to $600 range each but they work nice (used at work).

Brian

I'd keep it simple. Electric, while convenient, adds complexity to a critical system. A manual valve is more reliable. Buy the best quality clamps you can find and use two of them. Cheap insurance.

I installed 1-1/2" Conbraco ball valves in mine. I had bilge pumps in the way, so the valves ended up on either side of the centerline stringer just ahead of them. I quickly realized, like a couple others said, that I would not be able to go-go-gadget arm them once the motors were in, so I cobbled up a reach-rod that runs through the motor mount angles from 1/4" stainless rod.

A couple other notes: Make sure you double-hose clamp everything, with good quality clamps.

If you use the standard issue Mercruiser radiator worm type hose clamp...then yes...you should use 2 of them mounted 180* apart. But if you use these clamps... http://www.eddiemarine.com/store/car...uct_list&c=111 ...all you will need is one clamp per connection. These clamps are the bull-of-the-woods in hose clamps and will hold well over 500 psi. Now whether your hose will tolerate that or not is something else, but be careful when tightening them up...they will crush whatever you are putting them on if you go too tight. These type of hose clamps are the only type that I use now, and I have never had a failure. They are somewhat pricey, but you wont have to buy hose clamps again either. Other places have these type of clamps down to 1 inch in size

Bringing the valves closer with solid piping also sounds like an interesting idea. I imagine it would need to be SS as to not have any dissimilar metals?

Use Full flow bronze valves. Better than brass and SS as far as as the dissimilar metal issue. Not really an issue for a boat not left in the water though.

Setting up a SS rod to use as a shut off works great. Nortech does an excellent job of this. I will see if I have some pics of one. They make an aluminum bracket to hold the rod.
I have also seen a cable used. This gives you a little more flexability in mounting. I believe it's a fuel shut off cable for diesel engines. It has a knob on one end of the cable. You push a button on top of the knob and then pull it out to shut off the valve. Works great.
I have some pics somewhere. I will poke around for them.
Eddie

Formula also uses the push rod idea.

Coast guard Regs require 2 clamps no matter what style they are.

My Cigarette has Morse 33C cable actuated seacocks. They are monted to the forward bulkhead, fitted to a t-handle.

I always thought any water hose below water line are supposed to be double clamped. But then Merc doesn't follow that ruling, so..???