4000 in the first 500 miles is quite high for a normal car. There used to be two schools of thought regarding running in:
If you want the engine to last, keep the revs down to 2500 for the first 500 miles, rising to 3500 until 1500 miles. Drain the oil at 500 and 1500 miles and then keep the revs below 4000 until you've done 2000 miles.
If you want a nice, free revving engine for competition use, don't go over 3000rpm for the first 500 miles then do as you wish thereafter, changing the oils at 500 and 1500 miles. You'll need to rebuild the engine every 15,000 miles but it will be competitive.
Sounds to me as if you're doing the latter and you'll end up with a responsive engine if not the most long lasting 😬. The oil in the catch tank may well be blow back because the pistons haven't bedded into the bores yet.
Edited by - Doug on 29 Jul 2012 22:50:55