I noticed that my 70 R/T S.E. Challenger also has rubber guards bolted to the rear bumper guards where most do not. 1st photo is next to my buddies T/A Challenger without them.
Sorry to hear about your misfortune with Scat. It's not just Scat and I order 10's of thousands of dollars from them all the time. The whole industry is struggling. All these sources that rely on overseas products continue to get delayed due to all the tarrifs and all other reasons for delays.
When he asked for a 70 Challenger, I thought of those extra wide moldings for a 71 Challenger, but since he said 70 I didn't think it was those. I for one always thought those 71 extra wide mouldings were ugly. Takes away the look of a perfect car.
Yes, you should have x braced the door jams from the inside before you started. I would triple check all of the door openings at this point and maybe even re-mount the door hinges and doors to confirm that all still fits and functions as it should now before you weld back in the new metal.
Most manufacturers will recommend a matching valve spring to your camshaft depending on lift and duration when more than your stock springs will handle. Some machining may even be required in some cases as well.
Usually two totally different style cages and sometimes even different materials of tubing from a drag car to a road race car. Definitely, check with the rules of your local sanctioning body of whichever racing you plan on doing.
Just slip your stock tip into the larger exhaust pipe you want to use, Mark the tip where it snugs up inside the new pipe and cut it off where needed and remove the baffles.
I like my 2012 R/T Classic with 84,000 on it now and no issues in 13 years. Eventually, I want to buy B5 blue H.C. to go along with my blue 70. However, I do love this color blue also.
I welded a pair of old Megs megaphone style tips on one of my buddy's cars before. I just cut them back for the 2-1/2" dia pipe we needed. I never heard anyone comment that they didn't look factory. At least not from the average street crowds. Now, the true date coded, numbers matching weenies...