ford B460 block main and rod sizes

i have an older b460 ford motorsports block that has the 2.75 main journals,and my question is what advantage does this really have?also i have the crower crank that came with it and that has the stock ford 2.500 rod journal size.that can be offset ground to the 2.200 size,how does that affect the rod journal oil holes or the strength of the crank?is it worth the money to grind to 4.300?the crank is 4.150 now.thanks for any advice.

Lower oil temps.

As far as the cylinder block's main journal bearing size unless you are making, say, 1000+ hp at 8500 rpm, then the benefits are negligible at best.

Whether or not you want to make any changes and/or spend the money on crankshaft modifications depends on the engine application. For example if you are running aluminum rods with a BBF big end that are of proper length then you could just run it as is.

Normally, the oil passages in the crankshaft ought not interfere with rod journal reduction & offset but you need to evaluate oil passage locations first.  How much you alter journal size and stroke depends on your build application. You could offset stroke and reduce the journal size to Chrysler, BBC, SBC, etc.  I wouldn't worry too much about structural integrity of your forged Crower crank as there are plenty of cast cranks out there with 2.20" RJs at 4.50" stroke. Yes you can offset grind the Crower to 4.30/2.20 and even farther than that if you want to go custom components instead of cookie-cutter parts. (Mathematically, you can go to 4.45"/2.200" without going undersize on the rod journals.)

Less bearing speed with smaller journals, but like Paul said, until its up in the high RPM range (think about the truck pullers who scream the engines well into the 8000+ zone for 30-40 seconds at a time! Yikes! ) its nothing you would notice by the seat of your pants.