Now, now boys. Don't be snippy.
As to the OP question above: I'd not want the bearing caps to actually stop the crank from turning. They're installed to hold the crankshaft in place gently. In fact, the crank should turn easily so the torque load will be taken by the wood block. The block of wood will jam the crank from turning without marring anything, and allow you to put a lot of torque on the nut. A flywheel lock does the same thing, but he has already removed the flywheel. Besides, the block of wood should be in the #1 crank throw position, so there is less torque along the length of the crank.
I have a 350ft lb Dewalt impact gun, but I prefer to use gentle (??) force rather than the hammering of the impact wrench. Also, a socket (needed for an impact tool anyway) and a long breaker bar is cheaper than an air or electric tool. Both pieces cost me about $45 at the local Sears Store (if any of them are left in your area).
Remember that you should NEVER use an impact gun to INSTALL any nut. Spin it on close with the tool if you want, but use a torque wrench to tighten it. NO nut has a 300 ft lb torque spec for tightening! Even wheel lugs are 30 to 80 ft lb and over tightening will warp the discs.
If you go to HF, get a large internal AND external micrometer (not a digital caliper - not accurate enough) so you can measure your bearings and journals. [Get a top-of-the-line Starrett set if you can afford it]. Also get some Plasti-guage to measure your installed clearances. You don't want to have this problem again. Don't order new bearings until you get some good measurements - you may end up grinding or polishing your crank journals because of the seizure, and will then need oversize bearings.
BTW - if you get a new micrometer, spend a few hours spinning it open and closed repeatedly. The threads will gently wear in and average any errors across the entire range of the tool. It makes them more accurate (used is better than new!). I have my Dad's shop class Starrett micrometer set from 1938 that will has been calibrated to better than half-a-ten thou. This is a case where the better tool you can afford, the better you will be.
You might also take your block, crank, and journals (con rods too) to a good machine shop and have them measure everything. You'll need them if you need to grind or polish a surface anyway.
I just prefer to spent the same money on a good tool and learn to do it myself.
Enough yammering. Sorry for the blathering everyone.
OK, more blather. Be sure to check the oil passages in your block and crank to be sure something isn't blocking oil flow somewhere. That would be the most obvious cause of your original problems.