Hey whats up. I have 451 with 440 source parts. I was planning on using their heads but they are out of stock. I cam across the Pro Comp heads and have read enough to determine they will work with my budget and having your brother own a machine shop I dont care what they look like out of the box. Question is will I have fenderwell header clearance issues with the raised exhaust ports? Im not sure if that appiles to B motors as well

You did'nt say what car your 451 is in. But generally the raised ports can be an issue. Your right in that on the "B" engine the deck is about an inch lower. So that should help...you can try using headers made for the RB and that will lower them even more.

I am guessing that since you said you will be using fenderwell headers that there is a good chance you have an A body car. In my Duster I run fenderwell headers on an RB block and when I went to the Victor heads with the raised exhaust ports I was still able to use my headers. The only issue I had was with the header hitting the master cylinder and changing master cylinders took care of that problem. I would think on a B block you should have even less problems.