[Scott68-93-97]

Unleaded gas will ruin your valve guides and exhaust seats. I had a set of 70 LT/1 heads off a Nova and converted to unleaded with new hardened exhaust seats and brass valve guides. leaded gas used to act as a lubricant for all that stuff. There doing the same thing with diesel in cali well similar we now have a fuel (diesels) with only 15 ppm sulfer or less, the sulfer acted as a lubricant in the fuel, I have been using a lubricant additive made by my pump manufacter (stanadyne) to help with this issue