'71 Exhaust system

[BBB454]

I just ordered my Flowmaster mufflers (5-inch 50s), and the speed shop that's going to install them suggested that I might want to change the front pipe because it is the old crimped style (stock). He said that if I can find non-crimped (mandrel?) pipe, it has better flow which will lead to increased HP and better gas mileage. (Besides, I'm going to have him put an "H" pipe in and we're not sure how rusted the old pipes really are.)

Two questions: 1) Has anyone made this change and did you notice any difference afterwards?

2) Does anyone know where I can find non-crimped pipe to fit my '71?

Thanks! :s

Barb

 

[GreyGhost]

Exhaust Systems

Barb:

I don't want to muddy the waters so to speak, but if you are going to replace parts of your exhaust system think about replacing the whole system. At the same time consider true dual exhausts. It would be a custom fit job but would definitely give you the extra HP you're looking for. Most good exhaust system shops bend their own pipe anyway and they would have to route both pipes through the single cross member relief. If you specify 2 1/2" pipe you will get the free flow and the sound you are looking for. Just a thought.
__________
:cool
Al

 

[1979toy]

I seem to recall that one of our supporting vendors has dual exhausts on sale right now (SS Vettes?).

 

[BBB454]

Sorry...

I should have said pipes, not pipe, it already has a 2.5" dual exhaust. I talked to my mechanic today and he doesn't think it would be worth replacing them, just replace the mufflers and add the H pipe.

I'm still going to check out some of our supporting vendors to see what they have available.

Thanks,
Barb:s

 

[72 Stingray]

Barb,

Both J.C. Whitney and JEGS sell aluminized pipe sections with 90 and 45 degree smooth mandrel bends in 2.5" and other diameters. I used them to connect the Flowmasters on my 72. JEGS, Summit, and other mailorder houses also sell H-sections to tie the head pipes together. Let us know how your car sounds when you are done. The Flowmasters alone on my car were quite loud and didn't have the typical "tinney" howl usually associated with them. My theory is that they only sound that way if you run at least some kind of tailpipe behind them (which of course we can't do ) You will also need to have someone make up a set of 2.5" exhaust tips if you want to keep the factory look. I haven't done it yet, but it shouldn't be too difficult. You just have to cut up a set of factory or reproduction tips, weld in 2.5" sleeves, and have them re-chromed or ceramic coated. Maybe someone make 2.5" versions already? I don't know.

Jeff

 

[BBB454]

Barb,

Let us know how your car sounds when you are done. The Flowmasters alone on my car were quite loud and didn't have the typical "tinney" howl usually associated with them. My theory is that they only sound that way if you run at least some kind of tailpipe behind them (which of course we can't do ) You will also need to have someone make up a set of 2.5" exhaust tips if you want to keep the factory look. I haven't done it yet, but it shouldn't be too difficult. You just have to cut up a set of factory or reproduction tips, weld in 2.5" sleeves, and have them re-chromed or ceramic coated. Maybe someone make 2.5" versions already? I don't know.

Jeff

Jeff, I am happy to report that the new Flowmasters (50s), sound EXCELLENT!! Just the sound I was looking for :cool, not too loud, but you know there's something under the hood (maybe people won't ask "is that really a 454?" anymore)!

As far as the exhaust tips, the installer cut off the smaller part of the pipe on the tips and welded them onto the mufflers. I'll have to buy new ones if I ever need to replace these mufflers, but they do look nice right now. The other downside was the amount of time it took him - 3 hours - which made my checkbook unhappy (he estimated 1 hour of labor).

And, call me crazy, but I'd swear I can feel a difference in acceleration too!! :J

Barb

 

[72 Stingray]

Congrats!

Your car probably now sounds like a big-block 4-speed should! I wouldn't doubt that you could feel a difference. The factory mufflers and smaller, crimped pipes were probably choking that big block to a certain degree. Have fun and try not to rattle too many windows or set off a bunch of car alarms!

Oh, and don't worry, your checkbook will get over it!

Jeff

 

[BBB454]

I guess I should have mentioned that I wound up keeping the 2.5" pipes that were on it, just had him install the H pipe and Flowmasters. He said the pipe was in good shape so it didn't need to be replaced...

As far as the loudness, it has a nice rumble while idling (as the installer said, you can hear every cylinder fire), and it makes a great "I'm taking off, get out of my way" sound, but once I'm actually underway it isn't much louder than the mufflers that were on it before so it doesn't interfere with conversations and radio.

Anyway it sounds G-R-E-A-T!! :cool

Barb

 

[BBB454]

Added benefit?

Am I crazy, or is it possible that the Flowmasters have also reduced the amount of heat being radiated onto the floorboards from the exhaust manifold? I drove it today for the first "long" trip since the new Flowmasters have been installed, and I could swear it's cooler!

Barb

 

[VetteGuy66]

Bein' Cool

I don't know about floorboard temperature, but you are now more cool.:cool Good luck!