Took my 68SS down to my local exhaust guy and asked him about what he thought would be the best setup for my mildly modified 396. He said that 3" pipe was overkill unless I was running some 500+ cu. in. monster. He recommended 2 1/4", maybe 2 1/2" pipe with flowmasters instead. This shop has done setups for my old 460 truck and my dad's 98 SS with great results, any reason to think he is off the mark with this recommendation?

Probably........but damn they sure look and sound impressive.
Seriously, depending on which engine builder you talk to and which issue
of Hot Rod.....er, or is that Pop. Hot Rodding?....you are reading, some say you cant have to large an exhaust system, while others say that too large will hurt low rpm torque.
I can speak from experience about how back pressure affects the 5.0 Rustangs. My buddy has a stock one w/ Supertrapp mufflers. When he leaves all the discs out, it really sounds good and even runs good. When he puts some discs back in the Trapps, it quitens down, and torque is NOTICEABLY increased.
I run 2.5 w/ Flows w/ my mild 396.....it hasnt sacrified anything.

Shannon

Eddie,

I have 3" exhaust on my 68SS with a cross over. The engine is a 462 cu BBC 11-1 with a Compcams 280 magnum and 3:55 gears.
It is pretty stout but I think your guy is partly right. My low RPM torque is not as good as I would hope. I my next plan is to copy a buddy's
GTO and put on 2.5" tail pipes from the 3 chamber flowmasters to the rear of the car. I also plan for the winter to go to 4:10 gears.
It sure is fun to drive even now though http://www.chevelles.com/forum/smile.gif

Jeff A. (ACES841)

i agree with your exaust guy i am running 2 1/2 pipes with a crossover and flowmaster 3 chambers on a 71 nova and it is dynoed at 400 at the rear wheeles with no probs. this exaust was put in to replace a 3 inch system and i noticed a gain in low end power, and no differance in the top end charge when the switch was made.

I have a 72 Chevelle with a 427 B.B.,350 turbo trans, & 12 bolt with 4.56 gears and 3" exhaust. I have no problem with low end torque.

You can contact the manufactures directly. They can give you some good information also. Thats what I did with my 66ss.

To answer the title of your post; YES.
BUT sexiness is a factor and may be worth the $$$ to you.

just a thought i went with 2.5 and 3 chamber flows on my 69 461cu in. and it runs very good top and bottom plus you can get the nice oval tips to fit, they look great. i don't think you need 3" until you get over 450 hp. john

I've got a 468 that I recently switched to 2.5" exhaust. Before it had a 3" exhaust that looked good, sounded great and (so I thought) performed excellent. After the switch, I gained A LOT of low end torque that I didn't know was there. So now the engine looks good, sounds great (still) and runs even better than I imagined. I'd say to stick with the 2.5" exhaust...you won't be disappointed. The 3" will be overkill unless you do some major mods to the engine. Just my .02

My '68 Elky SS with '71 LS-6, 2" Hookers, 700R4 trans, 4.10's, and 3" exhaust system w/Flowmasters picked up quite a bit of bottom end grunt since installing 2.5" tailpipes. It also eliminated a ton of resonance. Future plans are to install a stainless steel exhaust system with 2.5" tubing using all mandrel-bends.
Clint Hooper
Wichita Falls,Tx