First, let me say this was a fun and worthwhile adventure. I think that doing the work alone and without a lift is certainly more difficult. Clam shell “On-Or-Off” will be a personal preference, however, with the unit on, be sure to use protective tape where you think contact areas are and where you think it is not necessary, then you will be ready.
With the OE muffler in place, I saw no access or a way of removing the top vent shield (just below the license plate area) torx screws to the sides are clearly evident and then from the back I could only see the pop rivets that attaches the screen to a bracket. So, this part remained in place during the removal process of the oe muffler. Note, if the license plate is removed, the two screws that attach the screen to the said bracket would now be accessible for total removal. However, not a big deal at this point.
With all attachment points removed and associated muffler brackets, no matter how we tried to rotate/push/pull/wiggle/cuss at this muffler, we encountered resistance from the right exhaust tube hitting the back of the transmission and be infull contact with the clam shell (remember that tape?) Finally, we delivered that hummer with one guy in the engine compartment and the other pushing on the tail pipes. Our baby was well over 50lbs (or whatever the weight is) and out of the car.
Thank goodness, installation is not what you read in most any car manual, “Reverse Of Removal Process” as the Heffner pipe was a snap to install. Loosen up the cats, get the brackets back in, put in the bolts, align up the exhaust pipes as best as possible, install the screen (large hole “Challenge Grills”) install the bumper and then tighten it all up. Finally, install the lower grill. Remove all that blue tape. Reinstall the belly pans unless it is time for new blood, clutch/brake fluid and anti-freeze, which is currently being completed on the car.
So, to remove Clam Shell or not, it may be a good idea if you want less worry-grunt-groan-worry will something get screwed up, but the shell flexes enough and with proper protection, should not be a big deal, just plan on contact with the unit and the muffler.
OE exhaust:
Heffner installed:
View from the top. See the little Philips head screws just under the license plate screws? Also, I’m missing one of the vent nuts/washers on clam shell:
Bolted into place:
Side view:
All in save for belly pans:
Appropriate use of OE muffler:
I’ll see if the video of pre/post installation can be posted a bit later on.
Thanks.
DJ.