How street able are these 340 stroker motors?

Is it cheaper to buy a kit or buy the parts seperatly?
I priced out the steel crank from dodge - $1000.00.
Whats the best choice for rods and pistons? hoping the block cleans up at .040. Can I use stock rods ?
Pulling the motor Friday night!

You just gotta price around. I bought all my parts separately because I wasn't in a hurry to get it done and looked for the best deals. In every case I bought parts that someone else had bought and for one reason or another never used them so I got new in box parts for just a little more than half of what they normally sold for. The only exception was the rods in which case I went with new SCAT rods. Like Flyfish said their nearly impossible to beat for the price and value. You can use stock rods but they aren't as strong and will almost always need upgraded bolts (ARP bolts) installed along with re-sizing. That costs nearly as much as buying a new set of SCAT rods. Plus stock rods will usually hit the bottom pan rail on the block so the block has to be clearance for them. SCAT's use bolts instead of studs and nuts so they clear the block fine. Their also a good amount lighter than stock rods. Lighter rotating parts means a longer lasting engine (as long as their good parts of course).

What horsepower level do you have in mind? I see a lot of guys recommend using a steel crank and it is of course the best but I agree with AutoX that a cast crank is fine up to 500 hp. That's what I have in mine and it's going on 6000 hard miles, but it is only about 450 hp so I'm not stressing the crank to the max.

Pistons are another consideration. IMO when doing a stroker you should always go forged because the piston speed is so fast on them they take a beating. I used Wiseco Pro-Tru pistons and they are super light and along with the light SCAT rods allowed my machinist to internally balance the rotating assy. without using any Mallory metal (that stuff is priced like Gold!)

If I were you I'd have the block sonic tested. Most will be ok at .040 over but you just never know. You want a good stable cylinder wall, not something flimsy that lets the piston rock around. You should also have it square decked. SB Mopar's are usually terrible on deck height accuracy.