I just dropped a freshly rebuilt 350 into my car and I have a slight exhaust leak at the manifold and no muffler but besides that this motor is insanely loud... Im not sure if its because it has higher compression or what but this motor seems way too loud right now...

I have to adjust the timing a bit and put some higher octane fuel in the motor but aside from those factors I cant figure out why its so loud...

Is it just cuz the leak at the manifold and the higher compression combined with a fresh motor that makes it so loud or is there something I should check?

Thanks In advance

 

And As an added bonus I just took it on a test run up and down the road and it feels like its not getting any power and I think it may be a vacuum leak but cant find any =/