You should not have any pressure in your fuel tank. Vented yes, but It shouldn't buld pressure. Chris
Seat & Fuel Filler Caps That seat , along with the rest of your truck , loks mighty fine . You have the WRONG gas cap ! there is NO relief valve in it ~ ALL Chevrolet trucks use the same fuel cap from 1937 ~ 1970 , look it up in the STANT catalog @ you FLAPS , it's a nice smooth cover thing with stainless steel polished instead of the original steel paint to match one . It is vented , no valve .
Yep thats what it seems to be. I pulled the relief valve out of the cap this weekend and it seems to have cured the problem. Would have thought when you order for a 59 you would get for a 59. Thanks again
Mark, that is a great looking truck thanks for posting the photo of it. BTW, the gas cap being fixed does not fix the problem of fuel in the oil. Have you checked the fuel pump yet? I have had fuel pumps do that tome on different makes of cars and trucks. I lost the engine on a 77 T-Bird I had some years back. Also check out post #7 on the link below ,https://talk.classicparts.com/showthread.php?t=12867 .