Sorry in advance for the lenghty rant just to ask one question!
No matter how much effort I put into getting prepped to do a project, something jumps out to derail me a bit...which is to be expected when mixing old with new, I suppose! It took me nearly 10 months to receive my EFI kit, and having done much of the preliminary work, I decided to have headers installed for me at the same time that I was getting the O2 Sensor Bung welded into my exhaust. Before purchasing the BB8's, I followed Sanderson's instructions about verifying that I actually had the original Big Block motor mounts installed...and thanks to Lock Doc's pictorial post, I was able to determine that I did in fact have the "year specific" motor mounts installed under my 454 in the forward position (there are only two positions, right?). My '72 Suburban originally came with a 350 Small Block, but the original owner (who worked for a GMC/Chevrolet truck dealership as Service Manager for over 45 years) used the correct '72 Only Big Block motor mounts when he did the transplant...so I believed I was golden. Not the case when the BB8's install was attempted by my "Header-Pro" and I was quickly called and given the bad news that the passenger side collector was hitting the frame and not allowing the mounting flange to seat against the head (driver side was not even attempted at this point). I did some more research and found an interesting write-up along with some pictures from when Sanderson developed and test fit the BB8's using an original Big Block truck. If I'm not mistaken, the Big Block truck they used was a '68 to '71 version...and they even showed that a cresent shape was ground out for the fittment of the motor mounts??? I'm confused by two things (actually a lot more than two but at this moment, I'll address the two): 1) Does Sanderson know that in '72, GM had a "one year only" motor mount for the Big Block trucks? And 2) Doesn't grinding an area of the frame negate the idea of designing headers that actually fit this application? Both questions are rhetorical, but you get my point, right? Now I have also read that there was a design change early on, so that could explain no longer having to grind the frame...which leads to my actual question to the much more experienced board members: Do the '68 to '71 Big Block motor mounts position the engine higher than the '72 only Big Block motor mounts? A higher fit is what my header-professional said was needed. At this point, I'll have to wait until my EFI is up and running before raising the 454 up (and possibly out) to determine what needs to be done to fit the headers...but I did get the O2 Bung welded in place after the passenger side exhaust manifold was reinstalled. Am I missing something obvious??? I'll add some pictures, but please ask questions if you think I'm overlooking something! Thanks for any thoughts you might have.
Woody
Collector contacting frame.
Gap between flange and head...primary tube contacting motor mount stand.
Passenger side motor mount stand.
Crappy side view picture of motor mount.
Driver side motor mount stand.