I am trying to figure out my sea strainer plumbing. Unclear about a few things.

I have transom mounted pickups to strainer Inlet with shutoff. Then comes something I don't get. I would be taking strainer out to the pump and pump to crossover, but for some reason, the strainers are set up with a Tee on the out side withe double 1 1/4" outlets. I don't get why two of them. I was thinking maybe they each go directly to the front engine ports but too big?

This is a twin small block Chevy setup with 2 strainers.

Also, with mercruiser pumps I suspect I need a pressure releif? I intend to run without thermostat until I find it won't work. Where should pressure relief be without and with thermostat?

I'll have a dump from the trans coolers and hope to include releif dump together with it.

Thanks for any help.

Water enters strainers on top fitting and goes to engine from bottom fitting.
The T could be for a pressure bypass or for a fresh water flush connection.

Strainer to crossover? Where is the sea pump in all this?

There is a hose fitting in top of strainer.

I'm still a little confused for sure.

Here are a few pics. As you can see in the pictures, the ends are threaded vs. barbed but I do know the hoses were actually clamped on the threads! I'm obviously changing to barbed fittings. Just trying to decide if and for what reason I need 2 on the output side.

I'm running 652hp small block 427's. I'm thinking plumb in a pressure gauge somewhere and see if a relief will be needed once I get them fired up.