[kc8oye]

i had my engine honed by a shop, that used a torque plate..

I also used a flat tappet hydruallic cam in my chevy 350.. so it got it's requisite 20 minutes @ 2000 rpm, then I drove the living **** out of it.. and it has more or less zero blow by.. i have a breather in one valve cover PCV in the other, and the engine is coming up for it's first oil change.. I foolishly forgot to write the milage down when I changed the oil after the break in period.. I think it's around 5000 now. (Been using a semi-synthetic oil) so I just let it be until it started getting 'black'.. and figure I'll change it now.
I broke in using Shell Rotella 15-40w due to it's high zinc content (that's good for flat tappet cams)
then after 500 miles on that, I changed it to Valvoline MaxLIfe 10w30 and haven't looked back since.. including over-revving the poor thing to 7200 rpm once...
my theory on break in.. is go or blow

[cobalt327]

Huge No-No is using any "STP"-type additive during break-in, or for the first 2k miles, just to be safe.

Generally speaking, no additives are needed- period, except for possibly zinc (for flat tappets), IMO.