having a couple issues

[HiImBrian]

I just removed the spacer I had between my exhaust manifold and the head to get rid of any possible exhaust leaks there may have been. I also replaced the 8 studs in the head and put on new nuts. My first problem is that I hear a wicked exhaust leak whenever I give it gas and rev over 3000 rpms. There is a slight crack in my exhaust manifold (which I will soon replace) but it seems to be coming down a little deeper. Would a tiny crack like that be that big of an issue? I'll check more into this when I get back home.

The other thing I noticed when driving to work this morning is when I down shift to slow myself down I hear a louder than normal crackling coming from the rear end of the car. This doesn't sound like the usual backfire gargle I've usually got which is why I am concerned.

thanks,
-brian