I'm having trouble figuring out which main and rod bearings I need. I've surmised that I need Grade 3 for the 1st main, Grade 34 for the #2, Grade 3 for the 3rd main, and Grade 3 for the 4th main.






Here's some photos of my crank and block.






I wasn't able to find any info for the rod bearings.

 

no one????

 

It would depend on the tolerance there is between the crank & the journal or the rod and the crank. If your engine is getting prep at a machine shop the technician should be able to tell you that precisely, otherwise the bearing have to be stock size, this is assuming your engine is in like new condition. To be honest I wouldn't gamble on that, you could at least do the plastic gauge yourself. A quick search show that PG is still used by a lot of backyard builder. Most shop now have a sets of OD and ID micrometers but that is much expensive.

I would suggest that you contact a machine shop, they can certainly help you, I'm sure it wont cost you big money. I hope this help you a little bit.

Check this out: http://www.carcraft.com/techfaq/116_...ter/index.html

 

The problem is that plastigage does me no good if I don't know the stock bearing size. Even a snap-on micrometer only has a precision of 0.001." I need a precision of 0.0001" in order to have the right clearance.

Buying a bunch of grade 0 bearings and then measuring clearances via plastigage in order to buy more bearings seems like a waste of time and money.