Main Bearings

[AMXguy]

I'm helping a buddy rebuild his 383 and his crank cam back .10/10 with a new set of bearings. the mains are all top bearings, or it seems to me.  I never remember having the holes and grooves on the cap side just the top, the shop says don't worry about it but it seems like less surface area to me, though it should oil better. is this going to be OK?

[hemiken]

Bearings come three different ways.   No grooves, half grooves (one side only), and full groove (both sides grooved).

The half grooved are the more recommended set to use, but full groove do have their advantages, mainly a race bearing.   So it may depend on what you will be using the car for...................   Just check your clearances properly when fitting them.

More feedback from other members would be a benefit to see what they preffer to use when building an engine.

[Chryco Psycho]

the arguement will continue for ever , the full groove feeds more oil to the load side of the brg [bottom] but reduces surface area , the 1/2 groove increases surface area but reduces oil flow to the load side of the brg
I have always used full groove but my machinist is the opposite & prefers the 1/2 groove ....neither of us has had a main brg failure unless the oil pump failed so what does that tell you ....I guess both ways work

[moper]

Just like CP says...

I prefer the 1/2 grooves..lol. If it's going to be an rpmmonster, than 3/4 grooves would be my next choice. I rarely use full grooved unless they come in the kit. But if you order full groove, you will get basically two top shells for each bore.