Our '71-74 Chargers are big heavy cars. The stock 14" rim/s tires really don't handle the cars weight very well. I originally put 15x7's with 255x50x15 on the car and they were pretty good along with larger 0.96" Mopar performance T-Bars and sway bars. When I started drag racing the Charger, i put 15x10 on the rear, and some skinnier fronts (don't recall, but they might be 15x5"?)
I would get the 440 source 512" stroker kit for a mild street engine that may only see 6,000+ RPM
For a hot street/bracket race build the 470" stroker is nice if you don't want the real short piston of the 500" kit.
I did the 451" stroker back around 1991 and it was good, but back then there were no affordable stroker kits like today so it was re-used 440 crank and rods.
My Charger now has a 500" stroker kit, but the engine was built to rev 7,000 RPM, and is 12.4:1 compression. Not really what you need on the street. The 512 piston is actually a bit longer than the 500 piston because the 512 kit uses a shorter rod (same for the 470").
Also, the 512 and 470 kits have right about zero deck height which makes getting quench distance pretty easy with a 0.040" head gasket.
With the 451 or 500 the piston sits about 0.020" below deck, so either a thinner head gasket or milling the block to get good quench distance between the piston and cylinder head.
I would get the cylinder head cc volume for the heads you plan to use, and the cam specs to figure which stroker crank, rod length, piston dish gives the best compression ratio for your combination. I guess you want to run pump gas, and a mild cam so you might want to keep compression ratio around 10:1?
The 440 kits I have used were pretty good, but not a drop-in kit. I'm not sure any aftermarket kit is? You will want to inspect all the parts and trial fit them before final assembly. The engine balance can vary slightly on how the pistons and rods are matched up (were talking maybe 3 grams worst case?) If you have a gram scale you can weight match the pistons and rods to get a good average for the balance.
On my current 440 based 512 stroker, I chose to try a less expensive un-balanced kit so I could have my machine shop balance the assembly, but there is not much if any cost savings. I also already had rings and coated 743HNK bearings, so I only needed a crank/rod/piston kit, not the full kit with the rings and bearings.
I might even try a set of gapless rings, but they are expensive, over $300 set.