Hi, The 1968 carburetor gasket I got doesn’t seem to fit right on my B1386681E intake manifold. Is that B1386681E a 1968 GS intake manifold? Does anyone know what carb to intake manifold gasket I need? Thanks in advance.
Quadrajet Power says to try this one so I will. https://quadrajetpower.com/flange-gasket-598-early-66-67-buick/ Were there 2 different intake manifolds for the 68 GS, one early and one late? My car was built in December 67.
It looks like 1968 part # was 1386301. This may be gasket I need and looks like one I pulled off car. https://quadrajetparts.com/quadrajet-base-gasket-thick-buick-1968-p-99.html But Quadrajet Parts says they are temporarily closed, unfortunately. I found 2 NOS ones on eBay for $30-$45, which seems insane. Does anyone else know where to find this gasket? Maybe it was specific to Buick and only used in 1968?
Looks like Fel-Pro makes the correct fitting one, part# 60057 https://www.v8buick.com/index.php?threads/correct-gasket-for-68-gs400-carb.289999/#post-2391102
Thanks. I put my carb back on with the original gasket so can’t get a pic of my exact one right now but it looks identical to this photo from eBay including casting number. I also just found casting # list on Team Buick and it’s listed as 68 intake manifold. It looks like there were indeed 2 in 1968. https://www.teambuick.com/reference/casting_numbers_big_block.php I couldn’t find a photo of the second 68 casting # 1383438.
with that intake carb pad I would use the one recommended by quadrajet power. If the "smiley" heat passage is active IE has holes drilled in its ends (the one pictured here does not) then you will need a specific stainless shim gasket to block the exhaust gases from getting into the air fuel mix. I think old buick parts or someone like that reproduces the buick shim gaskets.
Thanks. The gasket Quadrajet Power sent me leaves open a hole in the channels that lead to huge vacuum leak. This is my exact intake manifold with the Quadrajet Power gasket they sent me. The one that was originally on it matches the Fel-Pro 60057. This is my exact intake manifold with my original gasket. I forgot to take a photo without any gasket on it. The Fel-Pro 60057 style gasket completely covers the smiley heat passage.
I didn’t notice any holes drilled in the smiley heat passage but will look closer when I take carburetor off again. Is this the shim you mention? https://quadrajetpower.com/heat-shield-gasket-combo/ I see the holes you are talking about on the photo of the 1967 intake manifold here. My 1968 1386681 doesn’t have those holes. https://www.v8buick.com/index.php?threads/carburetor-mounting-gasket.335216/
Ok by recommended you mean their second recommendation for the 66-67 gasket. If I don’t have holes in the smiley passage then I don’t need the metal shim they used on 66-67?
That is the 67 430 manifold and does indeed require the "special" gasket. Last one of those I had , tapped and plugged the passages.
It looks like to me that they had those holes/passages in 66-67 as an attempt to heat up the bottom of the carburetor in cold weather. It didn’t work too well, caused vacuum leaks with that steel plate, and led to corrosion issues. Here is some history on that. They also tried it on other GM cars. https://www.corvetteforum.com/forum...-tech-info-the-hot-slot-manifold-problem.html Then in 68, Buick evidently decided (maybe last minute) to get rid of the exhaust passages, but their intake already had the smiley channel, just without the holes. Without the holes in it, I don’t see what function it provides, so they maybe decided to cover it up. Then in 69, they got rid of the channels completely. Photos of the 69 intake manifold I found show a similar design baseplate just without smiley channel. So in 68, the intake manifold doesn’t have the holes, so nothing to plug. Then even though the channel is there, it doesn’t provide any function at all that I can tell, so evidently Buick decided to cover up the smiley channel without the holes with gasket material over it. The 68 gasket is also a little thicker than the 66-67 gasket, 0.093” vs 0.062”. Summit and everywhere I found it say the Fel-pro 60057 gasket fits 68 only 400/430 cars. https://www.summitracing.com/parts/fel-60057
After additional communication with Quadrajet Power they now offer the correct 1968 400/430 intake manifold base gasket https://quadrajetpower.com/flange-gasket-697-1968-buick/
I'm sorry I dropped out for a few days. Yes I meant the gasket recommended and linked from the qj power site is the right one to seal your intake to the carb baseplate. And yes since your intake doesn't have the drilled holes in the heat channel you do not need the stainless shield gasket. Glad you got it sorted out!
I posted comparisons of available 1968 gaskets here https://www.v8buick.com/index.php?threads/correct-gasket-for-68-gs400-carb.289999/#post-3381243
