No harm done, your very qualified and educated. No offence to the original poster either, but I'd rather be errr on the safe side with a newbie with most likely a sub-standard build and go ahead and tell them to be extra causious with break in. I HIGHLY doubt that the engines we are most likely giving advise for are built with the high standards and tolerances of Ferrari/Maserati. Piston engines have round pistons, bores and rings, I think main bearings aren't in question here as there is very little break in, but flat surfaces like side housings along with critcal side seal to corner seal tolerances vary GREATLY from builder to builder. If its too tight, you DON'T want to load it up till it wears its own tolerances, something that NO piston engine has to deal with. They have valve seals (again, round) and maybe a cam to either lifter or tappit to break in which in reality doesnt matter if its at high load or not, it doesn't know as its just simply RPM based. So, better safe then sorry. I know its sucks to be restrained, but come on, its only for a 1000 miles........... And I bet if you actually did the math, it would take the average joe 1000 miles to equal 1 hour of straight up run time on a dyno with load and RPM for minutes at a time.

~Mike...........

I agree the motors in question probably wont be built to the tolerances the motors I built in Italy were...

I also concede I will probably give around a 500 mile break-in before I go all out constantly on the motor, but I will also be trying to load and break-in the motor the whole time I am driving it as its a hobby car and not any kind of daily driver...

The last post you made makes the most sense to me personally... If someone built a motor themselves in their garage and aren't professional engine builders with proper measuring equipment, I would recommend an extended break-in procedure as you suggested...

If the motor was built by someone professionally and they did it properly it shouldn't require that much break-in time (personal opinion, not fact).

That being said, I think that I will back off from this thread... Thanks for your insight and counter points Mike.

- Chris

or your could live in the country and work up a good hour of straight driving with no traffic (other than the amish) :) its nice to live in indiana.

nice read guy, i appreciate ur opinions. i told my builder what i was doing and he said i was babying it too much. i just wanna make sure the bearings break in properly.