Cuda and its new 360

Which Speed Pro pistons are you looking into? I dont know of any with a 4" stroke, they are for stock cranks, 3.31 for 318s and 340s, 3.58 for 360s...

If you go with the 4" crank:
use forged pistons. They do make hypers for that, Keith Black does anyway IIRC, but you dont want a hyper in taht application. the piston speed with a 4" crank is much faster, and tthe ceiling for saftey with a hyper is about 6K. If you plan to rev it to there at all, use forged. For the extra couple hundred, they are more than worth it. The rods and crank must be checked out before you use them, by a qualified performance shop. Eagle is one of the brands that HAS to be looked at, the rods cycled, etc. Assume they will need a little work to get them "right". Cheap parts need a little attention to get good, but then will far exceed the stock type stuff strength wise and be well worth the cost. You will need to get the right bearings for the larger radius on the cranks..DIfferent suffix, I cant recall what they are, have it at home. Dont use I beams from Eagle, or Scat, or anybody else that sells them cheap (my opinion here..). Heads will be on the small side, even when ported by a good porter. They will work just fine, and make mad torque, just dont expect huge horsepower or rpms from them. They need the biggest valves (2.05/1.60), the bowls cleaned up, the pushrod pinch widened a bit, and gasket matching, plus the exh side ported. Polishing is a huge waste of effort IMO. It's money that can be spent better. Keep the static compression down around 9.5:1. run a cam that is around 240* @ .050, with more on the exh side, with lifts under .540".
As far as machining for the block. I do this : install ARP studs in mains, align bore/hone, square deck, bore and hone, deburr, clearance for stroke. Any less IMO is not a performance build made to last. It's a stock rebuild, that will work, but leaves some power/longevity on the table. Internally balance the rotating assembly. Very important. It's the right way, makes more power, makes more smoother, and makes parts changes later down stream (like TQ convertors) easier.

For a 360(3.58) stroke: Any hyper piston is fine for use to 6500-7K. Forged is better, but heavier. Crank is cast, so balancing gets more $$ with forged. Stock rods w/ARP bolts. Street rings, and that's it. Heads, dont go largest valves, 2.02/1.60 is fine. Cams, hydraulics say around 220*.050 duration, and a little more on exh. The 110-112 centerline cams will run strong all thru the rpm band, as stated earlier by Rumble. Pushrods..use what the engine tells you to. If you need to keep the compression up with the heads being milled, then you may need shorter ones..Adjustable rockers means new pushrods. Dont buy early and expect them to fit perfect..Wait until the shortblock is put together, and the length checked. The 408, when geard and tired properly, will go faster than mid 12s. The 360, will run mid 12s all day, but feel softer around town at lower engine speeds. Machining is the same, just use ARP botls instead of studs, and still do the align bore/hone.