TBI to Carb Progress Pics. (Almost Done!)
Reply #15 –
We took the valve covers off my friends 390 in his 74 F100. He used Pennzoil up until that moment, he had heard it did that, and once he saw it he freaked. He cleaned it all up and started using Castrol or Mobil 1 I cant remember, but when he tore down the engine to start his rebuild it was still clean. He experienced alot of bubbling while using Pennzoil too, when he pulled the Distributor.