308 snorting and popping

I have excessive snorting and popping on overrun. 1978 308GTS, with a custom true-dual exhaust by PO, currently running test pipes. i notice alot of air leaking around the test pipes, which i have been told contributes to the popping. i took the test pipes off, and they were loosely bolted on with no gasket material. i will replace those.

however, the union upstream from that (see below), is there a gasket there? and should i replace it, and if so is it the same gasket as with the test pipe. I stupidly didnt check to see if those two connectors were leaking. that junction looks like it hasnt been opened in 30 years, and before i wrestle it apart i thought i would check. any thoughts would be appreciated.
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yes, but is there a gasket at the end of the header (see pic with arrow above), i am assuming there is, and was wondering if it is the same part number, and whether or not i should crack that union open in the interest of hoping to solve excessive popping (leaking air). it looks like it hasnt been opened in a long long time..

 

well i took everything apart, and there wasnt a single gasket anywhere (a few were in there, but so severely corroded they werent doing anything). So i replaced them all.

the end of the test pipe that goes into the custom muffler doesnt have the sleeve bit, it just has mated ends, so i slipped a little exhaust gasket material in there, and we'll see in the morning if the all the popping and burping is gone.

 

i put everything back together again, and the popping is about cut in half. it sounds very good, and just having a major completed everything is really tight and the car runs up very nicely. I am not sure if i should continue to track down the rest of the popping, or just let it be. Here are two videos, it sounds alot different under load.

any thoughts are welcome

http://www.youtube.com/watch?v=hTROSgKhyzk

http://www.youtube.com/watch?v=uTxm-j1UI-w

 

The car runs amazing, screams effortlessly right up to redline. It just pops on liftoff. Bear in mind the exhaust system is a little more than two old cherry bombs, nearing the end of thier life.

 

The issue with the snorting and popping continues. And now sometimes under very hard acceleration there is a sidewalk clearing backfire (wha-bam!!). Not always, only sometimes. The popping on lift off is all the time. Entertaining, but a little too much.

I pulled the old exhaust off, a homegrown system, and where the mounting rods are welded to the exhaust there is a pretty serious hole, exhaust flows freely out of it, and it is before the cherry bomb on one side, and after the cherry bomb on the other (both side welds are broken). Would air getting in at this location (before the muffler) create or contribute to the excessive popping? The whole system looks shot (see pics).

I found a used Tubi on craigslist in minneapolis for a great price (see pics 3 and 4), and it should be here next week, so we will see if that cures the issue. it needs to be cleaned up, but seems like a great find.

I guess if it doesnt cure teh popping it must be the header gaskets. The back side gasket was just replaced.

Thanks for any help or thoughts.
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Looking into that Len - have a great weekend, hopefully you can get the 348 out, and the weather complies. 75 and sunny here in Marin!!