[Sackett]

did you check the block for any warp-age and have the heads resurfaced?

 

[Sackett]

testing for hydrocarbons in the coolant will answer the head gasket issue. I had one car with a slight intolerance in the block that caused a overheat after gaskets were done. The other line of thought is that the radiator is getting clogged up. Have seen that after head gasket repairs too.