I just got my 1989 LA318 rebuilt and I'm wondering what oil I should use to do the break in and what type of break in should I do.

I'm not sure what weight to use but since I have roller lifters I don't need the ZDDP additive right?
I had it rebuilt with cast rings. The cam is new, regular stock model. Reused the rocker assembly. I'm thinking 5w30 for the break in with no additive.

I'd use what ever oil you plan on using for normal driving. I'd also use the Zinc even w/ the roller stuff. Just make sure you prime it up real good. If it's carb'd make sure the carb is full of fuel and you have good spark. I was told after the 20 minute break in to do a smokey burn-out to seat the rings...
I used semi-syntho 10-30, and additive when I broke in my solid roller 440-6.

A break in additive would still help they're supposed to have stuff to help seat the rings also

I would still use a good hi zinc oil like VR1 in 10/30.

Cast rings?

Hope you want a short life. Cast rings have two benefits. They are cheap. The break in almost instantly, no additives needed. This one of the major reason old school engines wheezed to 100k miles and news ones don't.

Your 89 318 should have had moly rings originally, I know my 87 318 does. No, you do not need a high zinc oil.

read "breakin secrets" at www.mototuneusa.com make a mark on the dampener 2&1/4" (35.5 deg) CW from the TDC slit & have the guy manning the dist to set it to that when it fires for the cam breakin (can capped). any leaks/issues dont think about it just shut it off/fix it/refire back to 2500 RPM & continue on with the 25 min breakin procedure. You want a zinc additive for the cam. gm eos or something similar. In preperation set the dampener to 15 BTDC then move dist so the magnet is dead even with the tooth (#1 compression/#1 plug wire). Thermostat OUT. shop fan in front of rad. fill bowl with a syringe & several pumps to prime the eng & confirm the AP is working. You want it to fire right away & immed bring the RPM's up. you in the dr seat to watch the gauges/shout orders , one helper to man the dist/timing light, another one top & underneath to check for leaks. You have ONE chance to get the cam and ring breakin correct & after all that time/money you want to get it right. As said I woulda went with Moly & they both want a different bore finish but you'll be fine. EDIT I missed that you have a roller cam so I am assuming no zinc needed.

It's TBI.