Soo...I'm going to pull the distributor on my 78 4.9L soon to try and get it to stop leaking oil. I've searched the threads for proper rotor alignment and marking the block and distributor plus retiming it. Now I'm wandering, do I just use standard O-rings from the hardware store or something specific? And can I use a product like Corning O-ring expander on the new ones? Thanks for the advise!

 

Maybe I'll call a dealership or just pull it and find out....

 

Anything petroleum resistant, buna type orings would probably work no problem. As for size, measure the inside diameter of the groove and the width. Mcmaster-Carr will have just about any size oring you need.