Exhaust Help Needed- Intermediate Pipe

[synoptic12]

Lucky that an exhaust forum has been added. I'm adding a new exhaust system, including muffler. There seems to be only Walker exhaust pipes available. So, I purchased the tail pipe (43770) and intermediate pipe (47577). My question is what is the "cut-off" bracket on the intermediate pipe and what cause does it serve. I do not believe that a bracket is attached to the current pipe but am unsure. Putting it on the lift tomorrow. Any and all input relating to the aforesaid is most appreciated.
1986 Oldsmobile Cutlass Supreme Brougham- 5.0 Liter (307 c.i.) Vin Y
* Diagram enclosed with some pictures.

 

[olds307 and 403]

Personally, I think dual exhaust is a huge improvement over Olds crappy crossover single system. I believe there is a bracket that bracket attaches to. I saw a similar hanger attached under the car when I was hanging the dual exhaust tail pipes.

 

[synoptic12]

Thanks. You could be right. Did not wish to add duels, due to back-pressure. I forget if my car is positive or negative back-pressure. No need in duels though for I have 7A cylinder heads (swirl port) and no manifold is available: only for the 5A heads (1985). Aside from triviality, I'm just keeping the original set-up.

*Any issues in hanging the intermediate pipe with cut-off bracket, "if not needed" and why do they refer to the bracket as "cut-off" as denoted in the Walker diagram?

 

[69hurstolds]

According to note 102 in the walker exhaust application page, it's telling you to "Cut off Bracket" to use it on your Olds. It also fits chevy Malibu and Monte Carlo...and I'm guessing they need the bracket.

 

[olds307 and 403]

Thanks. You could be right. Did not wish to add duels, due to back-pressure. I forget if my car is positive or negative back-pressure. No need in duels though for I have 7A cylinder heads (swirl port) and no manifold is available: only for the 5A heads (1985). Aside from triviality, I'm just keeping the original set-up.

*Any issues in hanging the intermediate pipe with cut-off bracket, "if not needed" and why do they refer to the bracket as "cut-off" as denoted in the Walker diagram?

Actually the Thornton manifolds, just needs gaskets and no doubt their shorty headers will work as well. I had duals on a 260 and actually found 1 5/8" shorty headers and 2.5" X pipe exhaust improved performance a lot. In theory the 2.5" exhaust should have hurt bottom end torque, it didn't and helped 3500 rpm and up big time. This is over 260 manifolds and maybe 1 7/8" dual exhaust. The 260 also has tiny port heads, maybe 8 to 1 and a peanut cam, so very similar to the swirl port 307. I have achieved 26 mpg imperial so far and should hit 30 mpg with the improvements I have done. In town is also good. Don't believe that back pressure non sense, velocity is more important. The factory exhaust was cost, quietness and emissions compliance. Flow is dead last, even the 442 exhaust was a joke.

 

[synoptic12]

Thanks very much guys for the input. My factory exhaust is 2 1/4 except from the muffler back which is 2". Why Oldsmobile conceived this idea is beyond me. As far as back pressure is concerned, I was always hesitant to that aspect. I believe that my 307 runs off negative back pressure as adjoined with the PCV valve (- Negative). I believed that creating more positive back pressure (in adding duals) would hinder performance. This could be untrue for I added duel exhaust on a 74' Olds Cutlass Supreme (Welded Y pipe) and never had any issues. The gas increased though.

Upon installation this day, the "cut-off bracket" attached to an upper bracket 'perfect fit'. However, the exhaust port opening was leaking some and a gasket and spring needed to be replaced. All is copasetic : finished. I'm not interested in upgrading the 307, too many roadblocks. I'm the original owner and have kept the car all original. If I did decide to go ground up restoration, I would most likely opt for a bigger bullet.

* In terms of flow in the 442 being underrated, I would certainly agree. My 307 has air injector tubes which I replaced some years back. The end point goes into the cat to allegedly lower emissions but if one cuts that tube, more horsepower is gained. The only detriment is a 'hissing' noise. Did not care for the air noise so the tube was re-welded. In the end, what does any of this mean, nothing, absolutely nothing. Again thanks very much guys for the assistance.

I do not recall if I ever posted my video but these are my wheels.