Sean,
If you are building for torque and low-RPM, you will save a ton of money on this build.
Aluminum heads are great for power, but I'd say they are a waste of money unless you want a big HP number on the top end. Spending $3000 for the weight savings seems foolish to me.... a set of 049 or 781 iron heads can be re-worked with larger valves and will give you PLENTY of torque for your application, and at a much more wallet-friendly price.
I don't think you need massive CFM numbers on your EFI system either. Again that is more of a peak-HP consideration, and I'll bet you could feed a BBC with 500CFM-600CFM pretty well if you weren't trying to spin it above 5500RPM anyway.
A lot of the really expensive parts are a result of wanting high RPM, or high HP (or both)... if you play the BBC game correctly you should be able to use much more common (and affordable parts) to get reasonable RPM capability and great bottom-end torque numbers. Using a milder cam will help your bottom-end, and will be more friendly for EFI tuning too.
This is one of those rare occasions where I'd say NOT to indulge the "Might As Wells"..... a hardcore, all-out BBC motor will cost you a ton of extra money but won't necessarily be better for your intended application. If you decide to start doing sand drags or whatever, then you can start worrying about aluminum heads, forged internals and all the other (really) expensive chit.
My vote is to get a solid, almost stock 454 short/longblock and make a few select upgrades (aluminum dualplane intake, for example).... throw your preferred EFI setup on it with a set of headers and peel the "f" out.
-G
