***Update***
Well...it appears I need to back-peddle a little on who screwed up with the fitment of the Sanderson BB8 headers! My mechanic friend (Jerry) finally got an area in his shop freed-up so we could start to figure out the motor mount issues, and after removing the stock manifolds and fitting in the passenger side ourselves, (this was the side that my so-called "Header Pro" provided pictures showing really bad interference with the fit), we slid the header in without issue??? Sure, it was a little close between the frame and where the "Sanderson Headers" nameplate is welded to the collector...but we still fit it in even with a rag in-between protecting the finish! When we took another look at the pictures that the "Pro" had sent me, we realized that he had attempted to install the header while aligned with the wrong bolt hole (which pushed the header forward nearly 1 1/2 inches)!?!? Now the primary tube easily clears the "single bump" in the middle of the motor mount perch. We will be grinding a little extra clearance into the frame where nameplate is...but it's not absolutely necessary...just preferred!
Then we started working on the drivers side (which the "Pro" never attempted as he couldn't fit the passenger side). At first glance, everything looked like smooth sailing...although it really helped having the Suburban up on a lift as this side goes in much easier from below! The header flange mated-up to the exhaust ports perfectly until we tried to get the bolts started? After a lot of attempts, we managed to get the rear bolt started, but just barely...and then we realized that the alternator bracket was keeping the front of the header flange from seating tightly against the front exhaust port! There was nothing unusual about the stock alternator bracket or bolt, so we surmised that someone at Sanderson forgot to grind a clearance divot into the flange!? We struggled with the two options: grind the alternator bracket or grind the ceramic coated flange??? Ultimately, I made the hard decision and chose to grind the flange as the interference also involved the head of the bracket bolt (plus, the hole in the bracket would have to be made into a slot!). It wasn't just a slight divot that was required as we ground in small amounts until we got the header bolts to finally thread in nicely. Jerry (the shop owner) had some actually customers to take care of, so we called it quits for the day...but we had made tremendous progress without having to lift the engine, alter the motor mounts (although we are putting in a new set of "caged" rubber mounts) or dent-up these beautiful ceramic headers...just a little grinding in a couple of inconsequential places. It was a really good day!
Woody
This area of Jerry's shop is a little tight, but it has everything I needed including a lift and a complete locking security cage surrounding it (PLUS...Jerry!).
Three things to note in picture: The bolt hole to the right of the flange that the "Pro" used; How much clearance there is when the primary tube isn't sitting on the "bump"; and the area with the purple rag...that will be slightly clearanced for the nameplate.
This picture was supplied by the "PRO" and it shows how the primary tube is resting on the "bump"...because the flange is 1 1/2 inches too far forward!
This picture shows how only a slight amount of grinding will be required to fully clear that retangular nameplate: A little by the purple rag and a little where the frame comes to a point.
This picture was also supplied by the "PRO". It's a little hard to see but it shows that the "point" on the frame hits in the middle of the nameplate, however, as shown in the previous picture with the flange properly aligned and rotated into place, it has just enough clearance to bolt in!