Hi all, I want to build a 440 6-pk engine from a stock 440 block. I also want to  increase the power and torque with mild improvements ie...balancing, different crank maybe, porting, and other internal (hidden) improvements, so that in the end it looks basically stock, but runs better than factory spec. What details specs in the form of crank, rods, pistons, etc... can anyone provide????  

Hi 71challey,
I assume this is for a 71 Challenger.
First off, you know 6-pack rods weigh a ton! Rotating weight takes H.P. and must be exterenally balanced. It takes a different torque converter or flywheel and weight will have to be added to a non 6-pack crank to get it to balance out.
The 6-pack carbs and intake work well and will feed much more than 440ci.
I would look to reduce the rotating assys weight and bump up the ci without over boring the block by more than .030". 4.15" cranks are readily available and with lighter forged "H" beam rods, lighter pistons, you will get an improvement. Even a stock crank will have weight removed during balancing with the lighter rods and pistons and that frees up H.P. and reduces stress at higher RPMs.
906 heads are ok with 2.14/1.81 valves but you can do better with aftermarket heads for the money. Check out "Indy Cylinder" Heads web site, they offer 906's and 452's in different build ups. Now that Edelbrock offers 2 Aluminum heads which flow very well for the money, to me, I would not put the money into a set of 906's or 452's. If I had to stay with cast iron, I would look close at stage 5's. If you up the ci, your cam will act like it's smaller, i.e bigger ci needs a bigger cam. 472ci with Edlebrock Victor heads, I would look at a cam in the 225 to 235 degree duration @ .050" range on a 112 but no less than a 110 degree centerline with at least .480" of lift. Back that up with a good (not B&M) med 11' or tight 10' torque converter, say 2,000 stall. That should do fine.  

I basically agree with thenoid.  I would rebuild what you've got, as it will make plenty of horsepower for your application while remaining stock appearing.  Bore and hone with torque plates, light weight flat top pistons, internally balance using stock crank and rods,  & bore oil pump feed in block.  Stroker packages will increase cubic inches without being detectablle externally, but your stock head castings will be a hinderance to 500 inches at higher rpm's (though they will make a gob of low end power).  452 or 906 heads are fine with a 70 degree throat cut, mild port work, and a good 3 angle valve job.  Stage 5 Mopar heads are a higher flow option while appearing stock (all aftermarket heads need some mild port work too).  Going beyond the basics with the 452's/906's gets expensive and you would be better off with aftermarket heads for the dollars spent.  Keep in mind you will toss a minimum of $2500 at a head upgrade by the time you purchase all the items necessary (bolts, rocker arms, shafts, hold downs, gaskets, springs, retainers, keepers, pushrods.  Obviously $1000 of that could be spent on the stockers, but most people will not put factory valvetrain parts on aftermarket heads.  Much more will be spent on Victor or Indy heads with their special componentry and header needs.  I do not recomend Indy heads for street use.  Finally, You should work with the cam company of your chioce to pick the right camshaft for your build .