Exhuast Flange Gasket

BAD2500HD · October 27, 2008

Need to put a new y-pipe on my '79 GMC 3/4T. with a 350, now the problem is i don't know for sure if there is suppose to be a gasket ( donut ) between the exh. manifold and the y-pipe ? some of the parts places i have called said there was and the other have said no listing for one . now the other thing is the ones that list a gasket said there is two diffrent sizes , anybody know for sure if there is suppose to be one there and the size ? my son took off the exh. and said he doesn't remeber seeing anything i even called one of the local GM dealers and they 1) could get the parts , to old and 2) had know idear if there was a gasket for them or not . so if you guys could help that would be great !! Thanks alot !

grampadirt · October 27, 2008

Need to put a new y-pipe on my '79 GMC 3/4T. with a 350, now the problem is i don't know for sure if there is suppose to be a gasket ( donut ) between the exh. manifold and the y-pipe ? some of the parts places i have called said there was and the other have said no listing for one . now the other thing is the ones that list a gasket said there is two diffrent sizes , anybody know for sure if there is suppose to be one there and the size ? my son took off the exh. and said he doesn't remeber seeing anything i even called one of the local GM dealers and they 1) could get the parts , to old and 2) had know idear if there was a gasket for them or not . so if you guys could help that would be great !! Thanks alot !

grampadirt · October 27, 2008

Need to put a new y-pipe on my '79 GMC 3/4T. with a 350, now the problem is i don't know for sure if there is suppose to be a gasket ( donut ) between the exh. manifold and the y-pipe ? some of the parts places i have called said there was and the other have said no listing for one . now the other thing is the ones that list a gasket said there is two diffrent sizes , anybody know for sure if there is suppose to be one there and the size ? my son took off the exh. and said he doesn't remeber seeing anything i even called one of the local GM dealers and they 1) could get the parts , to old and 2) had know idear if there was a gasket for them or not . so if you guys could help that would be great !! Thanks alot !

OOPS,sorry about that last post,not sure what happenned....My 79 motorhome & 77 p/u both have 454s,and both have metal doughnuts and both are dual exhaust.If I remember correctly I got 'em at Pep Boys....I would think that 350s are the same...not sure.Hope this helps.

g'dirt

kuhl_530 · October 27, 2008

Need to put a new y-pipe on my '79 GMC 3/4T. with a 350, now the problem is i don't know for sure if there is suppose to be a gasket ( donut ) between the exh. manifold and the y-pipe ? some of the parts places i have called said there was and the other have said no listing for one . now the other thing is the ones that list a gasket said there is two diffrent sizes , anybody know for sure if there is suppose to be one there and the size ? my son took off the exh. and said he doesn't remeber seeing anything i even called one of the local GM dealers and they 1) could get the parts , to old and 2) had know idear if there was a gasket for them or not . so if you guys could help that would be great !! Thanks alot !

Hopefully I can help, I work at an auto parts store. If you have a 350, you have three options. First of all, is it canadian built? If it's not, does it have a converter? My catalogging shows no part number for the canadian built, or the u.s. built with a converter, but do for a 79 350 w/o converter. They're all the same pipe size, though, and I would have to guess they all take the same part number. I come up with a gasket made by the "walker" company with a part number 31400. Hope that helps.

pennzoil29 · October 27, 2008

I know my '72 and '74 both had the donuts. When the y-pipes rusted through I changed them both to dual exhaust. I think it cost me like $100.00 more to do this, than just the cost of the "y" alone.

BAD2500HD · October 28, 2008

Need to put a new y-pipe on my '79 GMC 3/4T. with a 350, now the problem is i don't know for sure if there is suppose to be a gasket ( donut ) between the exh. manifold and the y-pipe ? some of the parts places i have called said there was and the other have said no listing for one . now the other thing is the ones that list a gasket said there is two diffrent sizes , anybody know for sure if there is suppose to be one there and the size ? my son took off the exh. and said he doesn't remeber seeing anything i even called one of the local GM dealers and they 1) could get the parts , to old and 2) had know idear if there was a gasket for them or not . so if you guys could help that would be great !! Thanks alot !

Hopefully I can help, I work at an auto parts store. If you have a 350, you have three options. First of all, is it canadian built? If it's not, does it have a converter? My catalogging shows no part number for the canadian built, or the u.s. built with a converter, but do for a 79 350 w/o converter. They're all the same pipe size, though, and I would have to guess they all take the same part number. I come up with a gasket made by the "walker" company with a part number 31400. Hope that helps.

Not sure if its canadian built or not never looked ! but it doesn't have the converter at least when i got the truck it didn't have one on it , the pipe i'm looking at is the walker but the place i'm am looking at has two sizes for the gasket ? think it said 2 1/32 and 2 17/32 . also some of the other places like i said have gave me two diffrent sizes for that gasket don't make much since but what do i know ! thanks