I just installed the Stainless marine exhaust on my big blocks and have a question, I still have the stock t-stat housing and there are 4 hoses (2 per side) running toward the manifolds.
There are 2 which are located below the t-stat itself and 2 toward the front of the housing which have plastic balls in it which are spring loaded.
The Stainless exhaust have a short stubby hose which is to connect the exhaust manifold to the tailpipe.
It has one inlet on the bottom side of the exhaust manifold.
Can I block off/remove/alter the t-stat housing to eliminate one set of hoses, or what do I need to do????

The hosing outlets with the ball valves are a bypass that allow water to skip the engine when the thermostat is closed. I assume you're still using the thermostat. You have 3 options:
1) Get a crossover and new thermostat housing. Eliminate the recirculating pump.
2) Plumb the current bypass and mail outlet on each side of the thermostat housing together. Route this to the bottom of the exhaust manifold. Plumb the manifold directly to the riser.
3) Plumb the main outlet from the thermostat housing to the bottom of the manifold. Plumb the bypass (ball/spring valve) outlet to a T in between the manifold and riser.
I've used #1 and #3, Merc uses #3.
Gary