I don't know about the POR 15 but I used the POR 20 on my 454 headers I followed the instructions to a tee... prepped, cleaned, treated, baked on, and it still pealed about 10 minutes after I first started the engine ! so after spending $75.00 on POR20 header paint and watching it peal before my eye's I would have been better using a couple of cans of BBQ paint "for $10.00"
Good Luck

Some people are like Slinkies, Their not really good for nothing... But they still bring a smile to your face when you push them down the stairs.

1951 3100 350 TBI Gallery Toddzilla... "$old"