Cross bolting the mains does basically NOTHING for cap walk. Been there seen that many times. Yet many believe it is the be all end all. There are other remedies for this and IMO a center counter weighted crank is your friend. As far as girdles go what can it hurt, especially combined with aluminum caps, lite bobweight and conservative on the timing. Do all that and I believe a stock block, provided the cylinder walls are good can last a good long happy life.
I agree, and I pasted my answer for n another thread
Weighing in on the girdle thing with my experience.
In 2003 I dynoed a megablock 4.15 stroke 4.50 bore 528 cube motor. Made 847 hp injected on methanol . I noticed cap walk on a crossbolted megablock, Max rpm was 7400. Bob weight 2432. I put a girdle on it. Didn't take away the cap walk issue. During this time we found a minor cracking the crank by #6.
I bought a rather expensive center weighted crank from Crower and took the girdle off. The C. W. Crank eliminated about 90 percent of the cap walk. I finally needed a little cleanup and align hone in 2019.
So IMHO the girdle basically can force a large portion of any movement into a vertical motion, which may help a little. BUT THERE IS NO TRIANGULATION to stop that vertical stress completely. So end result? IMHO they may be of some benefit, but not enough for a lot of stressfully builds.
Properly done, an add on girdle would be 3 inch or more tall, or thick, if that is how you would view it. That would require a rather short oil pan, like a dragster 10 qt . The big deal about it being so tall is it would now be so rigid it could transfer stress to the pan rails in all directions, not just lateral.
