33 Exhaust Issue

[GlennC]

Both transition exhaust tubes between the headers and mufflers seems to be hitting the lower 1” x 1” chassis tube through which they pass causing a thumping sound through the floor boards at certain RPMs. If I try to raise the exhaust slightly in order to create clearance it seems to put the engine/motor mounts in a bind. I thought about bending the chassis tube slightly but I’m hesitant to do so. Do you have any suggestions on how to create clearance in this area.

Thanks,

Glenn

[Dgc333]

Dent the pipe where it is hitting the frame. Hot rodders have been doing that for as long as there have been hot rods.

[FF33rod]

Pictures, chassis number (gen 1 vs gen 2), engine config,... will all be helpful in getting specific answers to your question. There have been different solutions for different configurations ranging from "should work as is" to "need to fab some spacers".... or you can beat the crap out of them to create more space...

Steve

[GlennC]

Thanks for the replies. This is a Gen 1 car with a 5.0 running gear (T5 trans). Both tubes are basically resting just above the lower tubes and at certain RPMs are bouncing on & off the chassis tubes. I've tried re-adjusting the muffler position but the rubber cushioned muffler hangers just allow the transition tube to return to its normal position. There is very little clearance top and bottom for the transition tubes to pass through as it is. I guess the brand of headers (BBK) used affects the pass through position of the transition tube. I thought of adding some spacers to the motor mounts to raise the engine some but I really don't have that much available space. The car has rear exit exhaust and some of that tubing had to be flattened a little to create chassis tube clearance so I guess flattening a couple more areas won't really matter if it comes to that.

Glenn

[wallace18]

On Gen1 you have to oval shape exhaust so it does not hit frame. I went with a custom exhaust that was 2". I never felt I was lacking any power on the street.

[FF33rod]

For what its worth, I have a 347 (302 block) with the recommended BBK headers and FFR standard exhaust with rear exit. I did manage to get everything to fit without modification and no hitting....
Not sure if the OP has a 5.0 Coyote or SBF

Steve

[RoadRacer]

Don't even get me started. I've removed and beat the everloving **** out of mine numerous times. Still rattles against the chassis all the time. I still love the side exit, but there just isn't enough room for it :D

So yeah, keep beating.

[Brave Salmon]

I had same issue with my 347 gen 1 car. I marked the pipes where they where they were banging and then used my press to flatten the pipes just enough to give me the clearance I needed to stop the rattling. Go at it slowly and be sure to measure the diameter of pipes when they are round first so you can get accurate measurement of how much you have reduced the diameter. you only need about 1/2-3/4". have fun.

[JimLev]

After you make some clearance wrap the pipe with this.
https://www.amazon.com/LEDAUT-Titanium-Motorcycle-Fiberglass-Stainless/dp/B011B99B0I/ref=sr_1_5?crid=1RLGD6M9YSNBK&keywords=exhaust+pipe+wrap+high+temp&qid=1669817030&sprefix=Exhaust+pipe+wrap%2Caps%2C142&sr=8-5

[GlennC]

Thanks for all the info. It's been so long since I installed the exhaust system I had to re-educate myself as to how it was installed. Removing the transition piece from the car might be a real pain to get it out to do the modification. It looks like that instead of un-bolting the transition piece from the shorty pipe at the square flange it might be easier to just un-bolt the shorty piece from the header and pull the whole thing out that way. This may not be that easy either because of the closeness of the rear shorty pipe nut to the firewall.

Any thoughts?

Glenn

[33fromSD]

Thanks for all the info. It's been so long since I installed the exhaust system I had to re-educate myself as to how it was installed. Removing the transition piece from the car might be a real pain to get it out to do the modification. It looks like that instead of un-bolting the transition piece from the shorty pipe at the square flange it might be easier to just un-bolt the shorty piece from the header and pull the whole thing out that way. This may not be that easy either because of the closeness of the rear shorty pipe nut to the firewall.

Any thoughts?

Glenn

Been a while since I did my build but if i recall I had to remove my transition piece to get my starter out that failed prematurely, and I think I removed the two muffler mounts on the side I was working on ( I think I used a small board between the frame on each side to hold the front of the exhaust up) and I had enough play in the whole exhaust to easily remove the transition piece.

Jim