just gone through my cooling system, changed to an alum rad and new upper hose. my car runs great and the oil is coolant free but the antifreeze that i drained from the rad and from the recovery tank (closed system with catch can) has a slippery feeling froth that sits on top of the coolant. is this normal? and if not, can oil get into the coolant without coolant getting in the oil? like i said the car runs strong. 440/727 stealth heads, street with some strip.

Antifreeze contains lubricant for the water pump bearings and seal. Some slipperyness is normal. That's why you can run into trouble running straight water, the bearings have no lube.

If you are getting oil in the coolant, if there is any quantity at all, the coolant will turn a crappy chocolate color. At least that's what happened to me on a 2.2 with a cracked block and a 360 with a failed intake manifold gasket. If you are still concerned, any heavy equipment dealer, Cat, John Deere, Case, etc. can probably test for oil contamination.