Art if you put the lines in the block your not cooling the cylinder head but returning it right back to the pump. when you put the lines in the head it cools the head between the two exhaust valves were most of the heat is. As for bigger rad you will be fine with what you have. The radiator that you have is bigger than the one i had witch was only stock one row. I drove my car for around 25to30 miles stoping at red lights and only got up to 210 when i got to the track. I think if you try and restrict the flow down it will help, just remember most of the heat from the engine is from the top of the block and the cylinder heads. Check your fan and make sure it turning in the wright diraction. Hope this helps. One more thing put a 20lb cap on her it will help.