So I'm putting together an H22a1 sleeved block and I have all H22a4 internals. The main bearings are 55mm and the rod bearings are from either motor are 48mm. No problems on the rod end, but the mains........ Should I have the mains tunnel bored to 55mm and use the a4 crankshaft and a4 main bearings? Seems to me like the crankshafts are fairly expensive. Advice.... Pros and Cons.... Help please.

 

I would look for a 50 mm main crank, should be able to find one for sale under 200 bucks.