That's very true! Many people have the idea that adding a main girdle to their $75 stock production block miraculously transforms it into the equivalent of a high dollar aftermarket block, and it simply doesn't. A correctly designed girdle, one that is aluminum and not steel, and one that requires the main caps to be machined flat so the girdle has the maximum clamping effect on the caps can add a small improvement, and have other benefits like dampening harmonics. But that's about all that can be expected from one.
