Cam specs w/o teardown???

Lemme get right down to the brass tacks of things. I've got an 88 GT which has had plenty of work done prior to my purchase about 6 months ago... suprises everywhere! Neways, it always ran pretty *****ty (idled like crap) so recently I converted to Mass Air. Idles like a dream at 800 now, however, it appears as though there MUST be some kind of an aftermarket cam in it. The idle is pretty inmistakable by everyone who hears it.

Question is... is there some way to check the specs of the cam / lift which would NOT involve tearing the engine down???

I appreciate anyones help and advice.