My buddies Dad put some kind of Cat engine and the manual trans in his Dodge after he broke the Cummins that was in it ( tons of boost ) . He has complained about it ever since , he had to do a 4 inch body lift to squeeze the trans in that I guess he can shift 8 or 12 times , according to his story the noise of the engine and transmission is considerable compared to the Cummins , he has spent a lot of time putting in more and more sound deadener as time goes on , the torque and towing is awesome . But just make sure the extra noise is within your level of tolerance , everyone is different of course , but I guess its all grins when he's pulling 20,000 lbs at 80 mph through the Smokie Mnts .