noises in my car after disc conversion

I think you may be right to look toward the rear end as being the noise, R&P. A roaring sound that increases with speed doesn't sound like any brake noise i've heard. Wheel bearings also come to mind, but your fronts are new so could be a axle bearing.
I'll let another member speak to the master cyl. with a conversion as i don't have direct experience with that.

P.S. that's gonna be a nice ride when you get it squared away:thumblef: