here are my thoughts
First stay away from the 496 ci build , the oil ring is over the wrist pin , it is basically a race engine .
Secondly all you really need are pistons , you can use a 440 crank & rods although it may work out as cheap to do a kit if you do not have a 440 crank & rods available .
With port work done properly the 906 will easily work for a great street strip engine & given that you want to use the stock 6 pack intake you will not need a lot more head flow , but if you want a max effort engine the aftermarket heads will be needed . I could prot the heads for you but shipping would kill either to ship the heads or ship me there !
If you decide to go with Alum heads I suggest the Indy EZ or Bulldog if you can find a set , you want a head with a small combuston chamber in the 78 cc or lower range , a flat top piston will make the best power but you need to have approx 11-1 compression to recover the heat loss to alum . the Mopar Stage 6 is a good head , I forget what the conbustion chamber size is for those , Mancini was clearing them out about 2 years ago for a steal . The Eddy & Stealth heads have too large combustion chambers to use a flat top piston & get near 11:1 compression
Stay away from the Eagle stroke cranks , you spend more on machining down the counter weights to fit than just using a stock steel crank , I have not used the Scat cranks btu they may have fitment issues like the Eagle cranks . You can get a race crank made in the us but you will pay $2500-3000 for the crank alone , un-nessisary what what you want to do IMO
