1972 350 single exhaust

[davischevy]

I put an original truck on the lift yesterday that still has the original exhaust. It's not clean, but original.

The thing that jumped out at me the most is the tailpipe. Notice the last 18" or so of the tailpipe is larger than the pipe from the muffler. I forgot to measure.

Also the downpipe on the passenger side has a curve at the starter, and on the driver side, a flat spot on top of the pipe.

I don't think many people will use this info, but here it is.

[davischevy]

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[Stocker]

Anything to do with the history of these trucks is interesting. That said, I would be amazed if that's the original exhaust but I'll take your word for it.... not trying to argue. Reason I am amazed is back in the day, gas was leaded and I assumed it was also corrosive, which would explain my need to have exhaust repairs done every few years or so on my K20. The thought of an exhaust system surviving this long is astounding.

[Ironangel]

All the hangers and clamps are factory. I just finished a resto on a 67 stepper with a 350 under the hood. Trying to find a 2-1/4" flared flange to fit the factory rams horn manifolds proved to be nearly impossible. I wound up using a pair of lazar cut 3/8 plate flanges with slotted holes to accommodate the 2-1/4" down pipes. PS. Lead is not corrosive and neither was the gasoline back in the day. Todays gasoline however is with the alcohol and moisture it absorbs, it's breaking down when you get it out of the pump!

[brown7373]

Pipes are aluminized now days, and I don't think they were anything but raw steel back in the day. I agree, replacing pipes was something done regularly every few years. Now days, I have aluminized pipes that are 25 years old and still look new. I now live in Florida, so maybe a few years with salted roads may change that, I don't know.

[muley]

Mine still has the original crossover single exhaust system. The pickup came factory with a 350/SM465 combo. I had an old muffler guy ( old as in he's older than I am, which is old ) look at the driver exhaust pipe that was "hammered flat" on top. He told me that was standard factory exhaust for a standard transmission so the clutch linkage rod would not hit the pipe. It now made sense to me remembering as a kid I had seen several like that over the years. Auto trans was an added option back then. Everything came with a standard trans unless you paid extra.

[davischevy]

Originally Posted by Stocker

Anything to do with the history of these trucks is interesting. That said, I would be amazed if that's the original exhaust but I'll take your word for it.... not trying to argue. Reason I am amazed is back in the day, gas was leaded and I assumed it was also corrosive, which would explain my need to have exhaust repairs done every few years or so on my K20. The thought of an exhaust system surviving this long is astounding.

You are correct in the amazed part.

The muffler was the first to go on these original systems, because of condensation. The muffler on this truck has been changed.

This truck came from Arizona and wasn't driven much after it go there.

The Y pipe is obviously original, because of the indentations.

I can't believe anyone would try to reproduce the tailpipe on a work truck.

The hangers don't prove the intermediate pipe is original, but it's very common for muffler shops to cut the lower part of the original hanger and replace it with a clamp.