Recently, I started noticing oil in the radiator of my '91 Olds Regency. I've backed-flushed the system and refilled with anitfreeze, and the oil still comes back. The engine is running fine, with no signs of difficulty. This makes me want to point toward an intake manifold gasket instead of a head gasket? Anyone confer? If it was a blown head gasket the engine would'nt purr as nicely as it is.....right?

can you confirm that it is engine oil and not trans fluid? maybe post a pic or 2.

I've dealt with a leak of Trans. fluid in a radiator before....after the flush there the trans fluid has a reddish color. The problem I'm dealing with is a dark brownish oil color.

I get it as well... it'* been like that forever tho.. and it'* always just a little bit of brown at the top of my coolant. If the motor has been running hot it'll be worse next time I check, otherwise it'* nothing really. I've done the intake gaskets, and it'* not that, and the trans cooler was pressure checked when I did the motor/tranny and I had that problem on the old motor too. A head gasket will bubble if oil is getting in the coolant, and it will not just be a little bit, it'll be a lot and get worse with time. I found when my intake gaskets blew, that it was more a problem of burning coolant than oil leaking in the rad, and the car never ran funny... just eventually wouldn't keep cool and everytime I floored the car there was a stream of coolant behind me towards the end of me pushing the time.

Verify if you have an oil cooler to the radiator. This could be where the leak is.
Only the SSE had them on the Pontiac line. Not sure on the OLDs.