Both conversions are not too difficult with stock parts. For power steering, you'll need a power steering pump, brackets to mount it to the engine and may need a crankshaft pulley with an additional belt drive. You'll need a power steering gearbox and hoses to connect to the pump.
For power...
Anything under $10K would be a good price for a complete convertible needing a lot of metal work. I'm not a resto-mod fan, but that is an option for some.
They are stock pistons out of a T-code steel crank 440. I don't know if they are forged or cast, but I believe they are dished not flat top with no valve relief. I would guess they are cast.
I put a full dual exhaust on my '70 Challenger. Went together nicely. Their clamps are a bit weak, though. You need the manifold p/n to verify they supply systems for the vehicle. I paid around $1200 for mine, probably around 6 years ago. Also sounds really nice (440 4bbl).
The fifth character in the VIN is your engine code (JH23G for example is a 318):
C = slant 6
G = 318
H = 340
L = 383 2 BBL
N = 383 4 BBL
U = 440 4 BBL
V = 440 6 Pack
R = 426 Hemi
I believe all R/T cars had U, V, or R engines in 1970. In '71, H code engines were in R/T cars. Not sure if those...
Not sure if you are replying to me, but everything I said is correct for a single cam V8 if the cam sprocket is keyed to the camshaft (which is the case for stock engines).
No. You only need the cam sprocket dot at 6 and the crank sprocket at 12 and the chain installed to have the piston and valve correctly configured. Ignition timing is determined by the distributor, but TDC only involves the cam and crank positions. Notice that once the chain is installed...
The clutch is likely fine. The electromagnet wiring might be open. You will need to remove the belt, center bolt and clutch/pulley assembly and put an ohm meter on the electromagnet coil (there should be two leads). You may need to remove the coil from the compressor (3 screws) to get to the...
Two things will improve handling. Maximize caster and lower steering gear ratio. Should pull to the right if the road is crowned. Do check all the steering and suspension bushings, though.