I don't know much about the Holset unit but the On3 76mm ball bearing should be good for a reliable 650ish to the tire. I've seen evidence of power in the 700hp range to the tire. I'd choose the On3 unit between the two....I just googled the Holset, and it only has a 60mm inducer measurement on the compressor side? And it looks like a T3 flange? So, that means the turbine is on the small side as well but I don't see any actual measurements for the turbine. That turbo, if it's the same one that comes up in google search, would be way too small on a built 347 I would think.