Sweet another blown big block!
I think 4:11 would be a little large, unless this is built primarly for the strip. For a cam 260-300 degrees of advertised duration
112-115 lobe centers. The less overlap the greater the boost pressure will build in the cylinders. If more overlap is used the cam will hold the exhaust valve too long while the intake charge is flowing in through the intake valve. This leads to the glowing hot header problem because the fuel air mix is not building pressure in the cylinders but running out the tail pipe. A lower boost pressure will occur. Also advancing the camshaft 2-4 degrees will shorten the intake charge time to enter the cylinder because the blower is speeding up the denser air fuel mix entering the cylinder. This will give the burnt fuel mixture more time to exit the cylinder.
Heads look good, I should get a set.
How much boost are you planning to run?
The cast crank should be fine for low your app unless you are running 10+lbs.
Consider getting a MSD BTM ignition box.
It allows you to adjust your timing retard up to 3 degrees per pound of boost. 15 max degrees.
This is what I am running in my 427 bbc
http://www.summitracing.com/parts/CCA-11-404-4/
I read up on your build thread, how much blower wine do you get. I seem to get relitively little. I am running the 174 low manifold weiand. I got lucky and made it fit under the stock hood. It is a tight. Right now I need a set of gears and a locker. I am also running 125cc cast iron oval ports. No stall and just a shift kit in the tranny. I have 2700 miles on the truck in 2 summers of driving. I got a couple of vids but the truck looks slow as hell because I found that the distributor had giant springs in keeping me from getting any timing until 4k.
enough of my .02
good luck