The real issue if you look at any newer car Alum rads are always isolated from the body in rubber mounts as they will not last very long mounted directly to the body & flexing , so brass is better unless you change the mounting for a Alum .
Yes some do crack , easily fixed !
The 302/308 swirl heads flow extremely well . the 308s will easily flow better than X or J castings , the 302s work well also
Dahm read too many magazines & did every expensive mod even tho the results were not good , the rear 4 link for example is not adjustable & the car would not hook up , the car could have been built far better for a lot less ##
That should work , it will tip the vertical shaft slightly but not affect the ratio , you may have to tweak the angle of the levers on the vertical shaft .
I Agree with the above comments , yes you can achieve higher spring rates with coilovers But generally this includes Rack & Pinion steering which doesn't work well in Mopars ,using pinto / mustang 2 parts .
T bars are superior , , weight is lower & further back in the chassis , easy to adjust &...
72 had a flush bumper so the 72 bumper & brackets work ok , the bumper is slightly different , 73-74 had the bumper moved froward as in the picture above
72 didn't have a filler panel in front of the grille which I do not see in your picture , 73-74 had the bumper moved forward & a fill panel
Other differences are the hood chrome & hood latch between 72 & 70