in about a month I will be starting a rebuilt 440 and want to do it right. I am told a 10w30 for break in and a good additive. Any suggestions for the additive.

might checkout what Hughes' has to offer. www.hughesengines.com EDIT Here is a very informative ring breakin article (5 minute read) "break in secrets" at www.mototuneusa.com. I'd suggest leaving the stat out, having the front end jacked way up (air pockets), inner valve springs out, shop fan in front of rad and having at least 3 helpers there to cover their areas: timing/dist, adding trans fluid, coolant/fuel leaks, you in the drivers seat goosing the throttle and shouting orders . and most importantly having it ready to light off IMMEDIATELY when you crank it: initial timing right (5btdc), accel pump squirting, battery up, confirming ahead of time the dist triggers a spark at the plugs and very important in pre assembly mockup checks confirming lifter bore clearance by w a clean bores/lifters and it lubed lightly with WD40 raising each lifter off of the lobe with your finger then let go & it should fall down onto the lobe w a resounding "thunk", if it doesn't the bores MUST be honed for proper lifter rotation.