Pro cam grinders recommend 0.904OD (Chrysler) or sometimes even 0.921OD Pontiac lifters for huge aggressive roller cams, since the larger lifters necessarily have larger wheels and can use higher cam lobe accelerations. They are heavy so figure that in when you buy valve springs and pushrods. And they absolutely demand a custom-ground cam; big lifters are not a drop-in power gain!
For the street, there are a couple of advantages: when one has a block machined for oversized lifters (or bushings), most shops can also correct factory misalignments in the lifter bores (at extra charge). But remember- you're redesigning the whole camshaft system here, even for more sensible hydraulic roller cams, so proceed cautiously (with an open wallet) and take the advice of your chosen cam grinder!
If you have a stock 351-C block that you've lost your heart to and it has worn lifter bores, bushing the bores back to stock (with corrected geometry) can also minimize oil pressure losses during running. Bronze bushings (as George said) run much smaller oil feeds than stock, which allows more oil at the bearings with a stock pump- always a good thing. And if your shop is very careful, the bushings can be built to protrude up slightly above the cast iron bosses so as to allow the use of a high-lift aftermarket cam without poking the lifter's oil band out of the top of stock non-roller lifter bores. If this happens, it causes massive oil pressure drops. So one might not need a weaker reduced-base-circle cam, with the bushings. But not all lifters will work here.
Interestingly, SBCs use stock 0.842"OD lifters and THEIR 'speed secret' used to be to install 0.875" Ford lifters on custom cams!
