Let me start by saying I don't know much about engines and reley on those of you that do. So my ZZ4 is installed.  The guy that put it in drove it 50 miles or so, gave it to me said have fun.  Don't red line it or go top-end, but otherwise I could drive it hard including going over 5k.  I have seen mixed posts on whether they are broke in at the factory before shipped or not.  Need some advice, I fear I have been running way to hard for only having a couple of hundred miles on it.

The ZZ4 has roller rockers so you shouldn't need to worry about the ZDDP level in the oil, but I would still pick up a container of EOS at a GM dealership's parts counter.  It's made for engine break-in.  Then drive it normally...not crazy...and regularly vary the rpms to give the rings time to properly seat, if they're not already.

Yep, I would hook the Vac adv. back  up, drive it like you would you pick up, use it but don't abuse it, don't lug it and vary your highway speeds, at 500 miles change the oil and filter, at 3500 miles change the oil and filter, at 6500 miles change the oil and filter, take the motor to 6000 rpm, at 10,000 miles beat it like a rented mule, thats how I broke in my street motors

I need to look at the GM install instructions, but it the guy said that put the engine in said that GM was specific on not hooking the vac advance up and very specific reasons why.

Brain, did the motor come with a distributor, and if did, did it have a Vacuum advance canister on the dist. and if it did, why would they send it that way if they are telling you not to use it,  THAT'S the reason G.M. went bankrupted, now I get it, without a Vac. Adv. you will get poor gas mileage and poor off Idle response, I had a coversation with another member who had troble with getting his engine to run right, it was a 290 hp GM crate motor and the instrutions say the same thing, can't remember who or what post, I tryed to impress on him to use it, after a couple of days he tryed it and all his problems went away, it was a different motor a different car so for now do what GM tells you, good luck an have fun with your new toy

[QUOTE=Gunslinger]The ZZ4 has roller rockers so you shouldn't need to worry about the ZDDP level in the oil, but I would still pick up a container of EOS at a GM dealership's parts counter.  It's made for engine break-in.  Then drive it normally...not crazy...and regularly vary the rpms to give the rings time to properly seat, if they're not already. [/QUOTE]

Okay.  GMPP contacted me and sent me their install insturctions:

Here is the break in procedure I got with my ZZ4 THIS YEAR:
The engine should be driven at varying loads and conditions for the first 30 miles or one hour without wide open throttle (WOT) or sustained high RPM accelerations.

8. Run five or six medium throttle (50%) accelerations to about 4000 rpm and 55 mph (if application is a vehicle), and back to idle (0% throttle) in gear.

9. Run two or three hard throttle (WOT 100%) accelerations to about 5000 rpm and 55 mph (if application is a vehicle), and back to idle (0% throttle) in gear.

10. Change the oil and filter. Replace with 20W50 racing motor oil (not synthetic) and an ACDelco oil filter. Inspect the oil and the oil filter for any foreign particles to ensure that the engine is functioning properly.

11. Drive the next 500 miles (or 12 to 15 engine hours) under normal conditions. Do not run the engine at its maximum rated engine speed. Also, do not expose the engine to extended periods of high load.

12. Change the oil and filter. Again, inspect the oil and oil filter for any foreign particles to ensure that the engine is functioning properly.

13. Do not use synthetic oil for break-in. It would only be suitable to use synthetic motor oil after the second recommended oil change and mileage accumulation.

to fix the dieseling try lowering the idel about 100 rpm, initial timing should be about 10 degrees BTC, heres, how the advance works, the mechanical advance  doesn't start to come in until about 1500-2000 rpm or more, that rpm is where your off idle to mid range performance is, lets say stop light to stoplight, without the Vac Adv., your motor doesn't have any advance except for your initial static timing of 10 degrees BTC which is not enough,  the Vac. Adv. brings in about 7-10 degrees more to cover the lack of advance from idle to when the mechanical advance starts to come in, at which point engine vacuum drops off which causes the vacuum advance to drop off so at WOT  the Vac. Adv. is not working, and you are running on Mechanical only, and if you do hook up the V.A. connect the cannister to the "timed port"on the carb.anips2009-07-24 14:14:58

[QUOTE=anips]to fix the dieseling try lowering the idel about 100 rpm, initial timing should be about 10 degrees BTC, heres, how the advance works, the mechanical advance  doesn't start to come in until about 1500-2000 rpm or more, that rpm is where your off idle to mid range performance is, lets say stop light to stoplight, without the Vac Adv., your motor doesn't have any advance except for your initial static timing of 10 degrees BTC which is not enough,  the Vac. Adv. brings in about 7-10 degrees more to cover the lack of advance from idle to when the mechanical advance starts to come in, at which point engine vacuum drops off which causes the vacuum advance to drop off so at WOT  the Vac. Adv. is not working, and you are running on Mechanical only, and if you do hook up the V.A. connect the cannister to the "timed port"on the carb.[/QUOTE] That is exactly the way mine is set up, runs great.