69 Cutlass S 350 rocket exhaust
December 17th, 2021, 06:14 PM
#1
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Location: Denton, Texas
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69 Cutlass S 350 rocket exhaust
I'm restoring a 69 Cutlass S convertible. I had the original 350 rocket rebuilt and I'm getting ready to put new dual exhaust on it. Every exhaust set I look at (Flowmaster, Pypes) tell me i need new downpipes that connect my manifolds to the exhaust system. Where can I find these downpipes? Do I have to have them custom built? Pypes sells a set but they say 455 engine only, not the 350.
December 17th, 2021, 06:38 PM
#2
Out of Line, Everytime😉
Join Date: Dec 2006
Location: Melville, Saskatchewan
Posts: 9,142
Those Pypes down pipes also fit the 350, they might need minor tweaking and sealant to fit. The 350 has 2" outlets vs the 2.25" BBO outlets and your stock manifolds need a block off cap on the extra outlet. Pypes have also had issues with pipes bent incorrectly, just as an FYI.
December 17th, 2021, 06:39 PM
#3
72Cutlass S
Join Date: Jul 2011
Location: Bakersfield, CA
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Last edited by gs72; December 17th, 2021 at 06:48 PM.
December 17th, 2021, 06:40 PM
#4
72 Olds CS
Join Date: Jun 2011
Posts: 6,657
This thread says they fit
https://classicoldsmobile.com/forums...ere-buy-63059/
i swapped my sbo for a bbo both w manifolds. I used the same down pipes and exhaust that was on the car just tweaked the exhaust pipes a little for fit.
https://classicoldsmobile.com/forums...ere-buy-63059/
i swapped my sbo for a bbo both w manifolds. I used the same down pipes and exhaust that was on the car just tweaked the exhaust pipes a little for fit.
December 17th, 2021, 07:13 PM
#5
Out of Line, Everytime😉
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Location: Melville, Saskatchewan
Posts: 9,142
December 17th, 2021, 07:34 PM
#6
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Thornton sells this performance small block manifold that has 2 1/4” outlets. Would these work with that Pypes 455 down pipe?
Also , forgive my ignorance but what’s a BBO?
Thornton's Small Block JR Exhaust Manifold
December 22nd, 2021, 06:25 PM
#9
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Posters above are correct, this- Thornton 350 JR + this- Pypes DOF10S Downpipe will allow you to connect to any 2.5" header-back system.
December 24th, 2021, 06:06 PM
#10
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Join Date: May 2016
Location: Saskatchewan
Posts: 540
Why not just take your car to a muffler shop and have them do the complete job. They can bend the pipes, and weld on the mufflers of your choice. That's what I did and am very happy with the job and the cost was similar to ordering the parts and installing them myself.
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