Strange symptom, what could it be?
 

Well what can cause oil/coolant to mix inside the engine but the radiator has absolutely no oil? :icon_confused:

blown head gasket

No as said is mixing only inside the engine and nothing going to the radiator.
I already installed the following:
*New headgaskets
*New heads

I'm disregarding the block as a possibility as is mixing a lot and if it was the block the radiator would have oil as well I even took out the water pump and no oil at all. if it would've been a freeze plug it would leak out the block and is not doing that.

Could be intake gasket leaking into the lifter valley.

If is that I will know today as am going to install the explorer lower and upper intake so I'll check on with that.

It is likely a bad intake gasket but it could still be a cracked block. Just because there is no oil in the radiator doesn't mean it isn't. The only way oil would get in there is if it went in under pressure. If a crack in the block was in an area that doesn't see any oil pressure, there is no way it could overcome the pressure of the cooling system to get in the coolant.

Another area on small block Ford V-8's that can be a culprit for this is the timing cover gasket. Coolant has to travel through water ports in the timing cover since it is between the block and the water pump. If the gasket between the block and timing cover develops a leak at one of the water ports it can leak coolant into the timing chain area which goes directly into the oil pan.

Oh, and don't use the Explorer upper intake. The lower is the only piece that is better than a regular intake. It's the same lower that the Cobra uses.

Well guys thanks for the inputs, I believe I found the issue.
I think it was the lower intake that might have had a crack or something because before I removed it I blew air into the block by the valve cover while looking inside the radiator and the water would make a lot of bubbles, after putting in the Explorer lower intake I blew air again the same way and nothing I tried it several times and nothing as well.

I changed the oil and filled up the radiator and turned on the car for a while and I still don't notice any signs of coolant in the block, I got my fingers crossed it stays like that lol.

Yeah but I cant use my mustangs upper with the explorer lower intake so I'll have to use it anyways.Even though is a PITA as I can't find a damn elbow and I need the car running.

UPDATE ON THE SITUATION
 

ok, well here is the situation am going through right now,

First after changing (cylinder heads, head gaskets,lower & upper intake + their gaskets as well), I thought the problem was resolved but here is what I see now.

*when the water level in the radiator is below halfway the water won't go into the block. Now when I fill up the radiator and even with the car engine off I notice bubbles in the radiator meaning the water is leaking into the block.

My thoughts are but I need confirmation:
1-the gasket or housing from the timing chain is cracked and when the water
level is low it doesn't leak into the engine because there is not enough pre-
ssure.
2- the engine block is cracked.

Questions are:
1)Has anyone had a similar situation?
2)Is it a higher possibility that it could be the block instead of the timing chain housing or gasket?

Please help I need the car and am going out of ideas thank you