Can a 5.3 be bored to a 5.7, 6.0 or 6.2?

To a 5.7 bore: yes, on iron Gen III 5.3 blocks — Jeff Smith has built two 5.7 L engines that way.

• The 5.3, 5.7, 6.0 and 6.2 all share the 3.62 in stroke. A stock 5.3 has a 3.780 in bore; the 5.7 bore is 3.898 in.
• Boring to 3.898 lets you use stock-bore 5.7 replacement pistons with the stock 5.3 rods (press-on wrist pins). The assembly needs rebalancing.
• Compression: with stock 5.3 heads (61cc) it would be over 11.2:1. Jeff pairs it with 5.7 cathedral-port heads (65cc) to land around 10.2:1 on pump gas.
• His stock-headed 5.7 with a Summit 218/227 cam made 430 hp at 6,000 rpm; a 5.3 with the same parts would be roughly 20 hp less.

Smaller step: a 0.030 in overbore on an iron 5.3 is no problem for wall thickness, and a flat-top 0.030 in piston raises compression from about 9.5:1 to about 10.4:1. Check piston-to-valve clearance either way.

We don't have a source on boring a 5.3 out to 6.0 or 6.2 sizes.