touching is too close, any year, you're fine at 3/4, probably OK at 1" with an original engine .... if it's more than about an inch it can pull too much air from the sides and not enough thru the rad core - look at a bunch of setups at a wrecking yard and you'll find anytime there's bigger space, there's a shroud to force the proper air flow .... if you swap a V8 in, use a shroud
Bill
