Exhaust Feedback

I don't have a real Ratrod old vehicle just my 89 F150, $700 truck I picked up a couple years ago to play with. Has a 302 with OD trans. Anyway the exhaust manifolds were busted so figure might as well go headers which I did. I have a couple exhaust cutouts to put in because I have them so why not. Big problem is the side gas tank makes it impossible to run the exhaust where I want to. Question is does anyone see why I could not run the exhaust outside the frame? i took a pic of the spot I was thinking and where it ends right now. I figure a couple 90* or 45s will get it out from under the truck. Thanks for any input. Jim

The biggest problem with running out side the frame is engine torque. The further out from the center line of the motor the further the pipe wants to move up and down. On an older vehicle the motor mounts can have a lot of flex. This usually leads to broken exhaust hangers loose headers and cracked pipes. You could try using some short stainless steel flex couplers running perpendicular to the frame to absorb the movement.

The early to late 60's trucks used to have the exhaust ran outside the frame for clearance purposes

Old Iron said:

The early to late 60's trucks used to have the exhaust ran outside the frame for clearance purposes

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Really? I've never seen that!

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Dr Crankenstein said:

Really? I've never seen that!

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Me either, the early 60' GM cars had the pipes and mufflers outside the frame and we were forever replacing the exhaust donut gaskets and lead pipes.

DozerII said:

Me either, the early 60' GM cars had the pipes and mufflers outside the frame and we were forever replacing the exhaust donut gaskets and lead pipes.

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You're talking X frames, no?

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Dr Crankenstein said:

You're talking X frames, no?

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You bet

Thank you for the responses. I am going to make this work. I'll probably do as suggested with the flex coupling. I'll also make sure to put rubber on the hangers to allow for some movement. Jim

i have studied this pretty hard and running the exhaust outside the frame and turn out in front the back wheels, is what i'll be doing to my grandsons truck (93) and his manifolds are busted too. being his is fuel injected i'll be running a small crossover for his o2 sensor.

I'm not talking from the factory
The muffler shops were doing this, at least here.
Here what they were doing.
This was due to the Chevy trucks having truck arm rear suspensions.

Old Iron said:

I'm not talking from the factory
The muffler shops were doing this, at least here.
Here what they were doing.
This was due to the Chevy trucks having truck arm rear suspensions.

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I see. That makes me wonder... what was under my '64 GMC? (Some Canadian GMCs were on Chevy chassis.)

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Dr Crankenstein said:

I see. That makes me wonder... what was under my '64 GMC? (Some Canadian GMCs were on Chevy chassis.)

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If it had the long arm rear suspension it would have had the exhaust in side the frame. Mufflers were mounted on edge vertically just ahead of the differential on each side of drive shaft, the tail pipes had 3 bends and exited behind the tire at a 45 degree angle to the box. I can't count how many I installed.

26Troadster said:

i have studied this pretty hard and running the exhaust outside the frame and turn out in front the back wheels, is what i'll be doing to my grandsons truck (93) and his manifolds are busted too. being his is fuel injected i'll be running a small crossover for his o2 sensor.

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That is where I was thinking to exit or through the fender.I am probably going to double 90* to get it from inside to outside the frame. I have OBD1 so I need the O2 sensor and got a header coupling with it i but I only need the right bank according to what I have read. OBD2 will need them both like you are doing. I really want to go carb but need to wait until swap meets open again. Thanks. Jim

Old Iron said:

I'm not talking from the factory
The muffler shops were doing this, at least here.
Here what they were doing.
This was due to the Chevy trucks having truck arm rear suspensions.

Click to expand...

That is very pretty. Jim

DozerII said:

If it had the long arm rear suspension it would have had the exhaust in side the frame. Mufflers were mounted on edge vertically just ahead of the differential on each side of drive shaft, the tail pipes had 3 bends and exited behind the tire at a 45 degree angle to the box. I can't count how many I installed.

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Thanks for the explanation. My truck did have the Chevy suspension, but that was 35 years ago and I have no memory of the exhaust. [S

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my 63 chevy ran inside the frame but we cut two holes in the cross member above the panhard bar so it cleared.

I had a 70 Cheyenne Super and the previous owner had an exhaust put on it where they ran the exhaust pipes outside the frame. They came off the manifolds and turned them out right behind the lower control arms. Was still tucked up enough they didn’t show.

Back in the mid to late 70's with the van craze, we installed hundreds of sets of sidepipes. It took a while to figure out on our own how to mount them to stop engine torque from making them come loose or breaking hangers. I remember lots of them coming back with leaks and pipes hanging.

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The side exit tips are off a set of boost thrush pipes. We have the whole side pipe but they were rotten in the middle so I was just able to use the tips