I have a gen V BBC, I need a part number and/or diagram for the o-ring and retainer for the dipstick at the oil pan. Any ideas?

Check with the parts guys at a GM dealer. That will probably be the easiest thing. They can pull up an exploded view on the computer. The o-ring is the same whether it's a truck or boat.
Eddie

never seen one on a B/B always just RTV on the tube...

I don't use the retainer, but I do use the o-ring. I just push it in with the o-ring and then silicone it in place.
Eddie

Thanks guys, I have went the silicone route and it never seems to hold up. I did notice I have been using the incorrect size oring. I have a customer that is a gm tech at a dealer, I may give him a call and have him look it up.

Jeff,
I have always had good luck using a Small Block Chevy valve stem "O" ring seal. I have a GenV in the shop that still has the dipstick and tube on it. I will try to remember to take a look at it in the morning, I need to pull the tube anyway.

Bill Koustenis
Advanced Automotive Machine
Waldorf Md

Good idea, let me know what you find out. I have a buddy that owns a machine shop and probably has one I could have.