CurtP,
I believe if you re-read my post, I never said anything about street vs. racing. I simply said that any motor can be pushed harder with the appropriate mods. For just about every problem encountered in hopping up an engine, there is a solution - your job is to figure out what the appropriate solution is and how much $ and/or time you want to spend.
You haven't been doing the hot-rod thing very long, have you? Billet cranks are easy to have made, as well as aluminum rods - I've done both for a one-off motor that didn't have any aftermarket stuff available. The crank and rods weren't all that expensive either - a grand for the crank and $500 for a set of rods. You just have to know where to go...
BTW, since this "block rating" is unofficial, who determines it? If it's the aftermarket manufacturers, then it's just advertising B.S. and totally useless. If it's based on someone elses experience, I wouldn't trust it very far either - how do you know how well they built the motor(s)?