I run a 4lb pressure cap on my A's. They are a little hard to find. I think a few of the A parts suppliers have them; but, I usually order them at my local Napa store. I have used reworked stock radiators and new ones. Snyders has the best deal I think. You can buy them all set up; but, are more $. The filler must be set up as high as you can- remember a little clearence for the hood. The water lies low in the filler neck- maybe a 1/4 inch. After filling it up 4 or 5 times you will see where it likes to be and just leave it there. Make sure the block is clean. Run a little Dash, Tide, Cascade, etc- something that will remove the years of sludge in the block. Flush it till the water comes out clear. Can take many flushes! Don't forget radiators do wear out and won't cool well. I run a thermostat. I also use Water Wetter. This has been discussed many time on here. Remember, the more you hope em up, the more cooling you need.