I've seen this touched on in a few other threads so I figured I would give the subject its own thread.

I've seen comments on both sides of the fence but is there any definitive proof that they add strength to the bottom end of a stock block?

'63 Dodge 330
11.19 @ 121 mph
Pump gas, n/a, through the mufflers on street tires with 3.54's. 3,600 lbs.
10.01 @ 133mph with a 250 shot of nitrous an a splash of race gas. 1.36 60 ft. 3,700 lbs.