I guess your stock s/c gaskets were leaking by real good & or no catch can ? , good thing you did the spacers anyway.
Same here at our track on Friday nights , at first real good , then it starts to go away with all the street tires.
That's what made track day so good , no street tires.
I really think that at the track everyone should be on DR's or slicks anyway , but I know their also trying to keep racing off the streets too.