I have a 340 and I plan on stroking it to 416. The problem I have is this. The block has rust in it. It's gonna have to be re-bored. I want to get this car running before I go and buy all the new stuff to stroke it, but I don't know if its worth it. If I replace the pistons now can I use the new ones for both the regular crank and then on the 4 inch crank or would I have to buy new pistons? Also, how hard would it be to change the crank later from a stock crank to a 4 inch stroker without doing anything to the pistons themselves? What I'm saying is can I rebore the engine, buy new pistons and get new bearings put in the engine now, then later go in and switch just the crank? Thanks for the help.  

No, you need different pistons for a stroker motor.
Maybe you should get a wrecking yd. motor like a 318 or 360 so you can drive the vehicle and save your money until you can do the 340 properly.  

Well, no. Two different animals. Sure you can do a basic rebuild now, but the 416 will need dedicated pistons-so is it worth it to do it twice? You could, but I don't like it. Do it once-do it right. It will save you time, effort, and money. So, I gather the 340 is no runner. If the rest of the car is anywhere near ready to roll and you want to drive it I rec. putting the 340 on the stand while you research the engine you really want it to be and start gathering parts. Get a running junkyard engine to shake the car down with if you want to drive it now. How bad is this rust? It is probably best to buy your stroker reciprocating assembly at least as a kit-even if you plan to have the block machined locally and assemble it yourself. Lots of specialist have put together various combinations of these kits with parts that they know work together. Lots of names-a few; Hughes Racing Engines, Muscle Motors, Barton Racing Engines, Hensley Racing Engines, Speed-O-Motive-the list goes on. Lots of info on their sites. Before when I was mentioning guys not knowing what their compression really was it's not just that you might have too little. Your potential problem is having too much. The flat-top slug that gives you decent comp in your 3.31" stroke 340 would give way too much if you are compressing another .069" of swept volume into the same combustion space. But the piston would not work anyway because if it was at zero deck at 3.31" it will now protrude .345" above the deck and launch your cyl head through the roof. The other .345" is of course how much further the piston will be pulled down towards the bottom of the bore. So, the "compression height" or "pin height" (the distance from the pin centerline to the piston crown) has to be compensated the right amount to get the piston top back down to a workable height. But, the flat-top at zero deck would still be too much comp. for pump gas because of the greater swept volume going into the same combustion space again. So-you will need pistons with a dished combustion area under the chamber. Various dish sizes are available as you will see when you look at the sites. Study up on quench theory. Find what the installed deck height of the various set-ups will be. You will find most rec. .040" clearance between the piston and the head to gain the detonation-inhibiting, compression-enabling quench effect. With good rods, bolts, and all, and limited rpm with no missed shifts-you can go a little tighter-.035" some go less-but don't, .040" is safe as long as everything is all straight and parallel. Parallel decking is just one aspect of quality block machining. I have seen the decks be several thousandths different from front to back. Anyway-no, I would build the 340 into the 416 once.  

That was so much easier-I gotta give up this education business!  

What do you mean by you should give up the education? I really do appreciate all the help. I don't have anyone close to teach me so I have to turn to here.
The car is a long ways off from running. But I also have a baby on the way, so you can see where that will conflict with buying parts. I'm just figuring my options. I decided to just take the block to a machine shop, have it inspected and cleaned and all that good stuff, then talk to the shop and find out what parts I should get. I'm gonna go ahead and build the stroker. I was looking though at the block today and it doesn't look very bad. I may be able to run it until I can get it rebuilt, although I don't know how good it will run.
Anyway, don't worry. I never rush into anything. I will research all I can before I buy that stuff. That's why I'm on here asking questions. Ask my wife, I always research everything. Thanks for the help.  

Just kidding. I've been enjoying it-if I minded, I wouldn't type so much. Keep asking questions. I, and probably everyone else that stops in here are all too glad to give a hand in helping get another good-running MoPar on the street or track.  

Cool. Thanks man  

Yeah, you know, and congrats on the baby. That can be a tough juggling act, and if the wife enjoys and supports the hobby it sure helps. My lady gets a kick out of it-so I'm lucky there. Evertbody starts somewhere, I started pretty young. I guess I used to stand on the front seat of the car and name all the cars going by thanks to my dad-of course. It was the early 60's growing up in the So. Cal car scene. By the time I was 6 I had cried to my dad enough about not taking me to the drags that he started taking me instead of going with his drinking buddies. We were at O.C.I.R., Lions, Irwindale all the time, sometimes at Riverside and LACR, and at Pomona, Bakersfield, and then Ontario for the big ones. We made all the big fuel shows and most of the the weekly ones. Pure, freakin' hot rod kid heaven! All the big names-all the mopar factory teams-I was hooked. Dad and I used to tour the dealers checking out all the new muscle, and they had a big lawn party with all the new GM cars every fall at the GM plant where he worked. And every couple of years he would take the money he made from GM and roll into the plant parking lot in a brand new Dodge-completely pissing off plant management! Ya gotta love that! I turned 6 in the fall of '67  when the '68 Chargers came out-wow! It was lust at first sight and I promised myself I'd have one when I grew up. I learned to drive in dad's '72 Charger SE 400 hp, and when I saved up enough from my part time job I found a clean, original owner 75,000 mile 383/330 that came with a service manual for my first car. Not having a lot of money and figuring I could do anything anyone else could do I proceeded to use that manual up-still got it. Sadly the car is long gone, but while I had it I learned the ropes of mechanics and bracket raced a fair bit at O.C.I.R. (R.I.P.) before they closed it down-made it to the semis once. Lots of great stories and very fortunate to see them all in their hay-day as a kid. I've always had the attitude that whatever I didn't know I could learn. I like to read and that's a big plus-but it's the doing that really teaches you in a way that sticks and gives that pride of accomplishment. So, dive in. If some cringe at the thought of you cutting on a valuable E-body-hey it's your car. Make what you want of it and enjoy I say.  

That's cool man. I'm only 26. I was born in 81. I actually didn't get into cars until here recently. I was kind of into them, but not into actually working on them. My dad passed away when I was 12 so I never had a father to teach me how to work on them. I joined the Marines and didn't even buy my first vehicle till I was 23. It was a pickup. When I got out I started in the oilfield. We do all the mechanicking on our own equipment and thats when I realized that its actually not that hard. I'm pretty mechanically inclined, so all that stuff started to make sense. I also don't like to take my vehicles to the shop and pay someone else, so I bought the Chilton's and did it myself.
I decided I wanted to build my own car after watching a friends 55 chevy at the 1/8th mi track. That's when I was hooked. I was actually looking for a camaro, but they are really expensive. A Challenger was my next choice. I found this one for pretty cheap and jumped on it. That's where I'm at now.  

Cool. I did a couple years at the Texaco refinery in Wilmington just up the road from where Lions used to be before I moved up here to the Rogue Valley in OR. Nice little car scene and drags about 5-miles up the road. Used to make the neighbors happy when I'd uncork the exhaust in the garage before running up to the track. Used to do that going to Orange County too-about a half hour drive-ha! Of course, I'm much more civilized now...