I've called Nissan and I've searched the forums but I can't find the answer to this. I'm wondering if the ca can be line bored and, if so, what bearings to use.

Yes it can be bored.
You will still use the same bearings, the purpose of line boring is to make the holes round.
The holes does not get bigger.

Does it NEED line bored? I've never heard of a CA having out-of-round main bores...

Yea, according to one machine shop it does but they can't do it so I have to find somewhere else to do it.

float_6969 wrote:Does it NEED line bored? I've never heard of a CA having out-of-round main bores...

I've had two like that so far. When you secure the main caps and girdle, the crank is supposed to be able to spin freely with little to no man-power (turned by hand). When the main bores become distorted and when you install bearings, main caps and girdle, the crank will be hard to rotate with your hand via the crank's nose and at that point you should disassemble and take your caps, girdle and block in for servicing. SO yeah, it does happen to the CA more often than most care to say.

Good to know! That's the first I've ever heard it mentioned. I wonder if it was something Nissan was dealing with via bearing clearances and when aftermarket bearings are installed, the issue shows up.

When you use billet steel caps and girdle you need to do it aswell

And studs.

x2 for the line bore.

When my first CA blew a heater hose and dumped the coolant, the engine overheated and the block warped enough to where I had to deck the mating surface to the head, and had to line bore the mains. We didn't figure out that the block had to be line bored until we were assembling it, and as Dee pointed out, the crank wouldn't turn by hand just under pre-torque load.