Side Exhaust on a 67

[Ron C.]

Hey guys, need your opinion? I'm interested in putting side exhaust on my 67 427/390 coupe. The car is restored but 99% original/correct. First, will I destroy the value? Second, if I add exhaust, should I use NOS side exhaust/parts or reproduction parts? Your thoughts are greatly appreciated? Thanks

[Kevin W.]

Re: Side Exhaust on a 67

My 67 300 hp came with side exhaust they look great and sound great but if you drive with the drivers window down for any length of time you can't hear out of your left ear. Other than that I like the look.

[Keith B.]

Re: Side Exhaust on a 67

Before you think about ask someone to take you on a nice long ride on the high way with the engine at one RPM Then ask your self of you still like them. I agree they look great sound great and sound great running up though the gears around town. Also if you have any paper work saying it should have out the back exhaust it might hurt the value

[Duke W.]

Re: Side Exhaust on a 67

They're also more restrictive than the under-car exhaust and will cost power. If you want a good sound, but not droning in your ear, get the off-road mufflers. Don't screw up what sounds like a nice example of a vintage Corvette. Post factory side pipe installations are detectable during judging and you lose a lot of points.

Sidepipes were pure bling, nothing more.

Duke

[Michael J.]

Re: Side Exhaust on a 67

I saw an interesting episode of Legendary Motor Cars on the Velocity Channel the other night. The character who does the Dream Giveaway raffles wanted Peter to sell him a '69 (I think) L71 (to pair with a 2013 427 'vert), that was freshly restored back to original specs by a supposed NCRS standards restorer. It didn't have side pipes (and had extensive documentation too), but the Dream Giveaway guy insisted they be installed (and watching the guys chop the rocker panels up and cut them out was painful) and then said "Side pipes were an option in that year, so it will not hurt the value and may enhance the value". Couldn't believe it. I like my '67 L71 with them, they are a blast, but if it didn't come with them, I would leave them off, Duke is right.

[George W.]

Re: Side Exhaust on a 67

Ron,
I have a 1965 395/425 side pipe coupe; when I fire it up it scares all the kids out of the neighborhood, that is not all bad, but it is hard on your hearing when you drive any distance. My wife does not like to ride in it because of the noise. My opinion is leave it original: if you change the exhaust; use NOS stuff; it will hurt the value and it will cost many judge points. Good luck with your decision.
Dr. George

[Ron C.]

Re: Side Exhaust on a 67

I understand the deduction. I've been told that even with the side exhaust, the car will still Top Flight. It's that strong of a corvette. I've heard that the side exhaust are more restrictive than under car exhaust but are there any dyno results to prove that? I have research the loss in power all over the internet and it seems that is just hear say.

[Gene M.]

Re: Side Exhaust on a 67

I understand the deduction. I've been told that even with the side exhaust, the car will still Top Flight. It's that strong of a corvette. I've heard that the side exhaust are more restrictive than under car exhaust but are there any dyno results to prove that? I have research the loss in power all over the internet and it seems that is just hear say.

Understand the deductions are extensive. Deducts include: total loss for exhaust system, bezels, tips, 3 hangers, clamps, ground straps, rubber seals, attaching hardware, missing front 1/4 brace, and rocker moldings. Damage deducts for rear valance, front fender lower lips, rear inner wheel wells, under body missing/cut rocker hangers, added notches and nut clips.

[George W.]

Re: Side Exhaust on a 67

I understand the deduction. I've been told that even with the side exhaust, the car will still Top Flight. It's that strong of a corvette. I've heard that the side exhaust are more restrictive than under car exhaust but are there any dyno results to prove that? I have research the loss in power all over the internet and it seems that is just hear say.

Ron,

You ask for opinion and I now believe you should put them on because; you don't care re loss of judge points, "the car is that strong"; you have no dyno data supporting the loss of power notion; future value of the car is not an issue and finally...my big block w/side pipes runs and sounds like a screaming jimmie...yours will too. Finally, I judged a BB '67 at a St. Louis Meet, a non factory side pipe car, with side pipes. I told the owner he will lose points and he said, "OK I like them and they sound good". He made top flight with the deduction; it was a nice car. So the bottom line is; it is your vette...Go for it!

Dr. George

[Paul J.]

Re: Side Exhaust on a 67

Ron,

I doubt that it will hurt the value that much, but what adding side pipes would do to your car is decrease the number of people who would want to buy it. I.e., it will take away a lot of the people who want a 99% original/correct 427/390. Putting it back to the way it was is difficult and expensive if you have someone else do it. You would be better off to find a 427/390 w/ factory side pipes, if that's what you want.

Paul

[Larry M.]

Re: Side Exhaust on a 67

Ron,

You ask for opinion and I now believe you should put them on because; you don't care re loss of judge points, "the car is that strong"; you have no dyno data supporting the loss of power notion; future value of the car is not an issue and finally...my big block w/side pipes runs and sounds like a screaming jimmie...yours will too. Finally, I judged a BB '67 at a St. Louis Meet, a non factory side pipe car, with side pipes. I told the owner he will lose points and he said, "OK I like them and they sound good". He made top flight with the deduction; it was a nice car. So the bottom line is; it is your vette...Go for it!

Dr. George

Agree with Dr George........ However, if it were my car, I would leave them off and install off-road mufflers for a little more sound, if that is what you want. Anytime you take a 2-1/2 inch exhaust system and neck it down to around 1-7/8 inch, it WILL cost horsepower......especially in a big block. To that there is no doubt. I have seen dyno results that show around 30-40 HP loss at WOT for the big blocks.

But sidepipes do have nice curb appeal and sound. That cannot be denied. I recently inspected a high $$$$$ former Duntov 1967 that the new owner also insisted have sidepipes installed as a part of the deal. They were installed and he is very happy at this time. This car was one of the first NCRS Duntov cars, and was restored by Dr Mike McCagh. A very nice car.

Bottom line, it is your car. I would use NOS parts and make certain that you picked a very good and experienced installer.

Larry

[William C.]

Re: Side Exhaust on a 67

With respect to the actual HP loss I never got an actual number out of my buddies in Chevy Engineering back in the day, but the most common description was "like putting a cork in the exhaust pipe" I also second the suggestion that you take a LONG ride with a friend who has a sidepipe car with a similar engine as yours, at highway speeds and assess your enthusiasm after that. The low restriction (off-road) undercar system is much better flowing and provides a reasonable "rumble" without creating a real nusense at highway speeds.

[Mike E.]

Re: Side Exhaust on a 67

Is it a St Louis or AO Smith body? Keep in mind that no AO Smith bodies had side exhaust. I was all gun-ho on adding side exhaust to my Smith body coupe until I found out that little fact.

Mike

[Michael J.]

Re: Side Exhaust on a 67

Is it a St Louis or AO Smith body? Keep in mind that no AO Smith bodies had side exhaust. I was all gun-ho on adding side exhaust to my Smith body coupe until I found out that little fact.

Mike

Well, since everybody will know the side pipes are not original with just a little inspection, I'm not sure it matters that a judge could make that determination much quicker if an AOS body. Then again, I have been "counseled" not to tell judges your car is an AOS body before they inspect the side pipes, who knows, maybe a few AOS bodies did come with side pipes.....you would hate to have such a rare deviation missed......

[George J.]

Re: Side Exhaust on a 67

I understand the deduction. I've been told that even with the side exhaust, the car will still Top Flight. It's that strong of a corvette. I've heard that the side exhaust are more restrictive than under car exhaust but are there any dyno results to prove that? I have research the loss in power all over the internet and it seems that is just hear say.

Ron,
I had my '65 fi engine run on the dyno with both sidepipes and the dyno exhaust. The sidepipes cost over 30 horsepower.

George