I can speak of the Indy block. But be sure to read the last few sentences of my reply.
The Indy block was delivered to me by Muscle Motors. It still needed bored and honed. The Unfinished bores delivered were about 4 1/4 in diameter, leaving someone building a bore specific engine to any size or to meet class specs. The line bore was perfect, also was the lifter bores, which were non bushed. The decks looked like they were finished with a chain saw, and in no way could be run without decking.
The block was $4200 + delivery.
Cause of the bores needing opening up near a 1/4 inch takes a while to bore, and being steel sleeves its hard to bore, and was expensive. I didnt want the local shop doing this major job IMO. I figured it would be easy to get the bore out of centers boring that much.
I sent my block off to Best Machine to be finished in that killer Rottler CNC boring/decking machine.
The tally for the finish bore and hone for piston fit, and install cam bearings, deck the block was $1000
I knew the engine was right though.
The block made good power but was limited in cylinder head cross section of the 440-1's. It made in the neighborhood of 850-875HP range and was a pretty reliable bracket engine, that had moderately low shift points. About 7200-7300 rpm.
About the only change I would have made, or modified on the block was the smallish oil return holes in the valley area. I opened mine up eventually over a 1/4" and counter sunk/chamfer around the openings with a 1/2 bit.
These blocks are a dry sleeve design with Priority oiling, they have billet steel main caps, and all five mains are cross bolted. I actually like how the main cap fits the block better than the Keith Black block.

I actually went with the Indy block to save some money, which really I didnt. The KB would have been about the same money, and IMO is a nicer/stronger piece. But these blocks would easily handle 1300+hp...So I wasnt no where near the blocks strength threshold.


Dont forget about the World Blocks...They have some nice options that the KB and Indy block doesn't offer. Like Duel bolt patterns for a chevy transmission. I ran this engine in a dragster and a glide was/is the only choice. So not having to use a adapter will save yous some money and headache also.
Also the World Block has means for internal oil pickup, which wasnt a real issue with me, but it would be a nice option in cars that people doesn't want,use or have room for a external pickup.