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As the title states - I was considering going from rear exhaust to an OEM/factory (not aftermarket) setup on my '69 vert. I like the look, but I've already got so much time and money into this car. I'm trying to determine if it's worth the effort. From what I can see, I'll need:
OEM side pipe/muffler assembly
'69 OEM side pipe covers
Mounting kit
OEM rear lower valance with no exhaust cutouts (as found on the '69 cars with factory side pipes)
From what I've read, the lower rear valance from the side pipe cars is not a direct bolt up - there are modifications that need to be done to the lower 1/4th of the upper rear panel that the lower valance attaches to. Is that true?
And, will I have to drill into the frame to install the mounting brackets or are there already holes there that I can use (I don't have ready access to the car to look for myself - it's at the paint shop)?
Bottom line - Is it a pain to convert a rear exhaust '69 to a '69 sidepipe car using OEM parts?
2020 Corvette of the Year Finalist (performance mods)
2019 C3 of Year Winner (performance mods)
2016 C3 of Year Finalist
Yes its a bolt on procedure. THere is a little triming under the front of the rocker panel, you can see it in the AIM. Its minor and its hidden.You can do the rear valence later at any point THis claims to cover the exhaust ports https://www.corvettemods.com/C3-Corv...html?pid=15699
I get that, but I have concerns that this isn't a simple bolt on procedure - the items I mentioned in my original post are the ones I am wondering about.
I'm hoping someone who has done this very procedure can provide some insight as to the overall process.
Last edited by Corvette-ZL1; Oct 19, 2022 at 03:39 PM.
If you want the rear valance to look like a factory 69 side pipe car (straight lines) you better decide before your paint shop sprays the color. It takes a little bit of fiberglass work to fill in the holes where the exhaust exits in the rear.
2020 Corvette of the Year Finalist (performance mods)
2019 C3 of Year Winner (performance mods)
2016 C3 of Year Finalist
Yes its a bolt on procedure. THere is a little triming under the front of the rocker panel, you can see it in the AIM. Its minor and its hidden.You can do the rear valence later at any point THis claims to cover the exhaust ports https://www.corvettemods.com/C3-Corv...html?pid=15699
I installed side exhaust on mine in 1972 and have not regretted it yet. At the time I really wanted side exhaust, the work to install was irrelevant. I just did it.
It's mostly a bolt on install anyway.
I did this exact mod on my 69. The biggest “pain” is the ‘glasswork on the lower rear quarters where the half-cutouts are today. You need to fabricate a perpendicular “face” to allow the rear valence to attach to the quarter at the lowermost point. I can shoot some pics if you like.
You need to drill one hole for the forward attach bracket. The frame already has the hole/slot for the aft (main) mount bolt. The lower front fenders need a trimming as well.
True OE parts are almost impossible to find unless someone has a NOS stash yet to be discovered. Paragon reproduces the covers for $2700 and several companies have the pipes for around $700.
Thanks all. So what I've read so far is that folks have either left the rear cutouts be, or filled them. But you can still purchase rear lower valances from a factory sidepipe car. Why not just go that route? Is it a direct bolt? I've read that it is not, and that you have to modify the part the lower valance would bolt to to make it work....
You can buy a rear valence that effectively fills the exhaust port. No, it won't look stock, but it does not involve any glasswork, or add work to undo. I've not been back to the dyno guy, but returning to the factory stock system on my car was like taking the cork out of a bottle. You can also acquire different pipes (check with RR above) that flow much bettter than the stock side pipes and fit under the factory covers.
I did this exact mod on my 69. The biggest “pain” is the ‘glasswork on the lower rear quarters where the half-cutouts are today. You need to fabricate a perpendicular “face” to allow the rear valence to attach to the quarter at the lowermost point. I can shoot some pics if you like.
You need to drill one hole for the forward attach bracket. The frame already has the hole/slot for the aft (main) mount bolt. The lower front fenders need a trimming as well.
True OE parts are almost impossible to find unless someone has a NOS stash yet to be discovered. Paragon reproduces the covers for $2700 and several companies have the pipes for around $700.
Thanks all. So what I've read so far is that folks have either left the rear cutouts be, or filled them. But you can still purchase rear lower valances from a factory sidepipe car. Why not just go that route? Is it a direct bolt? I've read that it is not, and that you have to modify the part the lower valance would bolt to to make it work....
You can buy an original side exhaust valance that will fill 1/2 of the exhaust tip opening. But the bigger issue is the other 1/2 of the opening. As the rear quarter panels were different from a side pipe quarter and a under body exhaust. That is where the fiberglass issue comes into play. The side exhaust quarter is molded to fill the other half of the exhaust tip opening where the under body exhaust does not.
You can buy a reproduction to fill in the other half of the opening. That way you will not damage the original quarter panels and allowing you to return it to stock with a few bolts.
As others have said.
If you can find and buy an original complete side exhaust system for your 1969. Get ready to spend $6K to $10K for a new never installed system.
To make it appear to be an original installed system.
1. Fiberglass fill in the outer half of the quarter panel opening
Trim the front lower fender along the sill to rear wheel well to allow clearance for the pipes
Rear wheel well the front small cover at the end of the frame is removed and a foam insulation block installed
2. Insulation is installed between the frame and bird cage along the sill area
3. The only holes to be drilled would be for the exhaust cover front mount to the frame and rear "Z" bracket.
4. The center exhaust hangers would be remover and a rectangular steel plate same thickness installed
5. Remove ground wires from center cross member
Maybe this can help there are images of the AIM factory install procedures.
This is my car: 69 L71 coupe, N14 option (Side Pipes)
It was a total mess when I bought it 7 years ago.
Some previous owner converted it to under car exhaust.
I wanted to go back to what the build sheet had on it; option N14
You can see the cut out fenders to allow tail pipe to exit.
You can use the lower valance that PJO has pictured above to fill the cutouts.
I went the other way taking it back to original.
My friend did the glass work.
Here are some under car pics.
These are the flanges you have to make.
So that can run into money!
Here is the Assembly manual section on the N14 option.
Notice on page 421 the front fender has to be modified (cutout) a little bit to accommodate the pipes.
My car already had this done at the factory.
But these pipes look wicked !
Ps. I bought the whole system from Paragon.
Long post but I hope it helps you decide. Good Luck!
I converted my 72 in 1978. All parts are OEM, straight from GM. As I recall it only took a couple of hours to do. Those pipes are still on the car, so they've lasted 44 years so far. I've never regretted switching for one minute, they get more compliments than anything else about the car. At the time I wasn't sure how long these would last so I bought an extra set just in case. I still have them, they still have the GM part number labels attached.
Even if you do the back the easy, "not perfectly original" way, only a Corvette guy would know. I'm a Corvette guy and I probably wouldn't even know. But I'd damn sure notice the sexy side pipes!
so, you have your list of needed stuff. shop for it when you find it. the stuff will fall into your hands a bit at a time. and if you change your mind the parts are all resellable as long as you didn't pay retail to get it all at once.
Worth it going to sidepipe setup on '69?
