When I swapped in my 6l, I did a cam swap, and changed the pushrods. Ever since I installed the motor, I notice a supercharger like sound. Its almost like alternator whine, but Ive been out of the audio scene for so long, I dont exactly remember the characteristics of it. Even with the radio off I get it (I still have the factory head unit, and my only amp is only on my sub) And it doesnt change with the RPMs too much, and you cant hear it once youre rolling pretty good. If I remember correctly alt whine goes away when you turn the radio/amp off. I'm thinking it has to be eigther a ground loop, or the pushrods, so I figured Id ask

 

I would think it's a bad ground somewhere. There's only like 5 or 6 ground wires to hook up during the swap.... lol