I want to put my 525sc aluminum head with a crossover setup but i dont know what is the best setup installation.

I have two choice betwen crossover one with bypass and the other without bypass What is the diference betwen them?
What they affect?

I have the CMI header with dump in exhaust , should it need to be blocked with this configuration?

Run with thermostat or whitout?

Thanks

if you use a thermostat you need a bypass. bypass cools exhaust when stat is closed.

Running the crossover with a bypass allows you to run a thermostat, running with not bypass does not allow you to run a thermostat, because if you do you will burn up the exhaust while the thermostat is closed. You shouldnt need to change anything about your exhaust setup.

I will need to change the oem merc 525sc thermostat housing so i will need new thermostat housing with 4 hose because my oem setup use 4 hose water inlet to the exhaust (two on the bottom and two on the upper side of the headers)
I have try to find one with 4 hose but i have just see the 2 hose thermostat housing available.
So if i can just use the 2 hose th housing i think i will need to block off the upper exaust water inlet and run with only two water inlet on the bottom of the headers.

I dont know what is your setup with similar engine, any help was appreciated....

My Formula had a 4 hose setup. http://www.offshoreonly.com/forums/a...a-dsc00325.jpg

The stat housings were bad so I went to crossovers. Origanly the water hose came in then went through the strainer then to the seapump then back to the coolers in the bellhousing. From there thay went into the back of the exhaust manifolds then out front of the exhaust to the t-stat housing then from the t-stat to the tail pipes.
Now the hose from the cooler goes to the crossover inlet and the 2 hoses from the t-stat housing go to the back of the exhaust manifolds and I installed the manifold to riser water transfer hose. http://www.cpperformance.com/p-12823...sfer-hose.aspx

The hoses that came with the crossover kit were the same as the water transfer hoses and I went to Napa and found the same molded hoses for about 9 bucks each. I don't have the Napa hose part number with me but if any one wants I can post it.