sbc
 

I'm not a real mechanic, I have a 350 sb ' with radiator liquid in the oil pan what can it be ?

It can be a number of things. It can be a blown head gasket or a cracked block, cracked head it is hard to tell.

how can i narrow it down

Well how is the engine running? Is it rough wont stay running or run smooth like there is nothing wrong with it? You can also do a compression test of the cylinders to see if there is one or two that is a lot lower than the rest.

Just thought of this does the radiator stay full??

Could be a leaking intake manifold.
Try pressure checking the cooling system. Autozone rents pressure testers. If that doesn't narrow it down then do a compression check. You might also pull the plugs and see if there are any that are wet. That could narrow it down to one cylinder or one bank.

I bought the car here off of racing junk, drain the oil two quarts of clear water came out first followed by thick sluggie light brown liquid, radiator was not empty 3/4 full

Would you by any chance have the ad # ??

What year engine, is it stock! if its an L 31 these engine are known to blow intake manifold gaskets( lower plenum gasket) need more info.

What fuel are you running, sounds like you might have a bad milking problem if the radiator still has water in it.

Thats what i thought, does it run on alky?