I hope I'm proven wrong but that "truck sound" when you barely touch the throttle sure sounds like a leak to me

It's still not too late to put on Percy's seal 4 goods before you bolt on the rest of the exhaust

But, I hope for your sake that I am wrong.

 

That blowing noise is the air pump....It took me a minute to realize that. Kinda scared me, but then I stuck my ear next to it.

I have both O2 sensors hooked up on the header now, so it runs a little better...Now I'm working on the Y pipe and the other O2 sensors...

My neighbor extended the passenger header O2 sensor for me.