Dirty,

Looking into your motor change, I suggest you put some length on the black hose out the back, not on your coupler. If you make the pipe longer you wont get the right back pressure. Not knowing how your pipe manifold will come out of the motor, I know out the back, but what is angle?...if it rides high or low. If the pipe exhaust manifold hook up is high you can heat the pipe lightly and bend to the down position. Be sure not to get to hot...its alum. Throw up some pipe manifold pics to see which set up would help. Photos say a million words...

Is it like this photo?