74chevyflat,

I can answer the first part of this question. Turning the crank .020 "under-size" and then buying .020 "over-sized" bearings is safe. You could go to .030 but then you are pushing the limits on a high horsepower engine.

Picking the "best" bearings is a coin toss. Just buy a name brand and you will be fine.

Now again this is just my choice but I like no grooves on the bearings. The oil supply hole rotates, so all parts of the bearing get oil on every revolution of the crank. Now others will have their thoughts so listen to them and then, in the end, you get to make your choice.

To balance or not? Again it is done by all the good engine builders to get every last bit of horsepower out of an engine, but do you HAVE to balance the crank.....no. Again this is just my thinking. I have built many engines and they all have lasted for years and years without balancing the crankshaft but who knows maybe they would have lasted EVEN longer if I had. Again if you have the money go for it but if things are tight just put it together and drive the wheels off.

Scholman

 

I usaually use clevite 77 main and rod bearings.

 

It's not how far a crank is turned that is important, it's how well it is turned. A properly turned .030"-.030" crank is better than a poorly turned .010"-.010".

Fully grooved mains are rarely used. Most mains are grooved in the top half with the bottom half not grooved. Some performance sets have the bottom have partially grooved. This helps if the rods can benefit from additional oiling.

Most brand-name bearings are of good quality. Some offer a tri-metal design while others use a newer, high-silicon content design. Some manufacturers offer both. High-performance bearings have there own pluses and minuses, depending on intended use. Do some research to find what is best for your applocation.

tom