GT40s also came on Explorer through mid 94. GT40s have 3 bars on the end and GT stamping, instead of the 4 bars and GT40P stamping. My heads came from a 94 Explorer. The Cobra heads have a smaller combustion chamber, raising the compression, as compared to the over the counter or explorer GT40s, hence I had mine milled .025. If you get the GTs, make sure you look into better springs, unless you run the stock camshaft.