Stock cast exhaust manifold gaskets?

[ancapn8]

I got a dynomax pipe kit and mufflers for my 76 K5 to replace the rusted leaky exhaust and I'm a bit befuddled by the manifold connections. The drivers side appears to have the 'donut' cast into the manifold, but the passenger side has the regular donut gasket. Am I supposed to put anything on the drivers side or is the pipe supposed to just mash into the casting?

 

[6872xtc]

The pipe should have a bell flange on it to mate to that manifold.

 

[Wes Harden]

no gasket for that collector.

 

[ancapn8]

The pipe should have a bell flange on it to mate to that manifold.

It has somewhat of a flange, but doesn't look much different than the other side. I wasn't sure if there was something supposed to go between it as I assumed the donut was like a crush washer (this is the first time I've messed with exhaust so I dunno, lol). I just couldn't comprehend the logic of GM having a donut gasket on one side and casting it into the other?

 

[6872xtc]

That's how it is supposed to be. I can't explain the difference either. I have even found some with springs under the nuts to let that connection move some, but usually no springs.

 

[diesel4me]

Very common on many GM SBC exhaust manifolds,for only one side to need a donut gasket...just clean up the metal casting before installing the exhaust pipe and it will not leak..

One engine swap I did with a friend was 99% completed on a Sunday night,we thrashed all weekend to yank out the dead engine and install the good one,and the lone thing holding us up was we had no exhaust donuts ,and we needed one for one side...
I needed to drive the truck to work the next morning--so we searched his shop for anything else we might be able to use..

I found a old battery cable in his rubbish can,I cut off about 4" of it and twisted the ends together in a circle,and used a propane torch and some solder & paste flux to "fll" the copper wire strands till they were completely covered..made my own copper/lead donut..
I put it on and tightened the bolts good on the flange...figured it'd get me by for awhile,till I got a donut gasket..but it never gave me any grief,so I just left it in!..it worked better than a real donut gasket..
I have seen some metal donuts used on some manifolds..

 

[ancapn8]

Very common on many GM SBC exhaust manifolds,for only one side to need a donut gasket...just clean up the metal casting before installing the exhaust pipe and it will not leak..

One engine swap I did with a friend was 99% completed on a Sunday night,we thrashed all weekend to yank out the dead engine and install the good one,and the lone thing holding us up was we had no exhaust donuts ,and we needed one for one side...
I needed to drive the truck to work the next morning--so we searched his shop for anything else we might be able to use..

I found a old battery cable in his rubbish can,I cut off about 4" of it and twisted the ends together in a circle,and used a propane torch and some solder & paste flux to "fll" the copper wire strands till they were completely covered..made my own copper/lead donut..
I put it on and tightened the bolts good on the flange...figured it'd get me by for awhile,till I got a donut gasket..but it never gave me any grief,so I just left it in!..it worked better than a real donut gasket..
I have seen some metal donuts used on some manifolds..

haha, that's a great story. Thanks for the help guys, I'm going to sandblast these this weekend and hit em with some eastwood exhaust paint to try to pretty them up a bit.