69 L-89 Coupe

[Stuart F.]

My son and I went to look at a friend's 69 L-89 coupe that he is interested in buying for his collection. Our friend is an ol time NCRS Vette man and has an extensive collection of top notch Vettes (and other cool cars), some of which he must part with due to a fall retirement move into a new (smaller) home up north. This car was frame off restored about 20 years ago, but has been well taken care of. It has a lot of pedigree documentation including Bloomington Gold, etc. We happened to notice that he had the side pipes added a number of years ago so inquired about the original rear valance and took a closer look at the installation. First off; the head pipes appeared to be 2", instead of the expected 2-1/2". Also, the heat riser butterfly seemed small as well, and it stuck about half way through it's travel - enough that it is doubtful that it could be overcome by the exhaust pressure, even though we could force it full open by hand. Yhe numbers all check out ok - it is an aluminum head L-89 435 HP, TI Ignition, 3 x Holleys for sure.

Now then, does anyone have knowledge of these 69 C-3 series Vettes that could shed some light on what we should expect with this car? Our current thoughts are that this side pipe installation is incorrect and my son should plan on restoring the system back to original, much as he may like and long for a side pipe car.

Thoughts please.

Stu Fox

[Joe L.]

Re: 69 L-89 Coupe

My son and I went to look at a friend's 69 L-89 coupe that he is interested in buying for his collection. Our friend is an ol time NCRS Vette man and has an extensive collection of top notch Vettes (and other cool cars), some of which he must part with due to a fall retirement move into a new (smaller) home up north. This car was frame off restored about 20 years ago, but has been well taken care of. It has a lot of pedigree documentation including Bloomington Gold, etc. We happened to notice that he had the side pipes added a number of years ago so inquired about the original rear valance and took a closer look at the installation. First off; the head pipes appeared to be 2", instead of the expected 2-1/2". Also, the heat riser butterfly seemed small as well, and it stuck about half way through it's travel - enough that it is doubtful that it could be overcome by the exhaust pressure, even though we could force it full open by hand. Yhe numbers all check out ok - it is an aluminum head L-89 435 HP, TI Ignition, 3 x Holleys for sure.

Now then, does anyone have knowledge of these 69 C-3 series Vettes that could shed some light on what we should expect with this car? Our current thoughts are that this side pipe installation is incorrect and my son should plan on restoring the system back to original, much as he may like and long for a side pipe car.

Thoughts please.

Stu Fox

Stu-----

ALL 1969 Corvettes, base engine to ZL-1, were originally equipped with 2" exhaust. 1969 was the only C3 year during which side exhaust was available. The 1969-style side exhaust was 2", too.

[Bill C.]

Re: 69 L-89 Coupe

Stu,

Do you want to put NOS under car exhaust back on or use aftermarket?
Did they use a after market rear valance filler panel (one made to fill in holes from exhaust tips) or did someone glass/fix it to look a real side exhaust car?

Depending on how the covers were installed, you may have to fix some fiberglass areas under the front fender. You had to cut away a small section close to the front to make
clearance for the pipes. If it was done nicely you should not have to much issue getting the correct rocker moldings to screw back on. I think that one of the 6 screws may be affected by
a sloppy cutting job.


If you do want to go the NOS route - give Paul Oslansksy a PM - he may be able to help you out with some items.

Bill

[Stuart F.]

Re: 69 L-89 Coupe

Joe and Bill;

Thanks for your responses. What we do with the car will depend a lot on whether my son wants to keep it for a fun driver, or perhaps correct it for judging. Still a lot of questions we need to find answers for. It's a non-air, non power steering smog equipped car which limits the fun factor here in central Florida. I manage with my 63 convertible ok, but then I just go out for early Sunday morning drives (as I just did) this time of the year.

Very surprised to learn that all 69's have 2" pipes. That's wierd to me.

Thanks again;

Stu Fox

[Jim T.]

Re: 69 L-89 Coupe

Joe and Bill;

Thanks for your responses. What we do with the car will depend a lot on whether my son wants to keep it for a fun driver, or perhaps correct it for judging. Still a lot of questions we need to find answers for. It's a non-air, non power steering smog equipped car which limits the fun factor here in central Florida. I manage with my 63 convertible ok, but then I just go out for early Sunday morning drives (as I just did) this time of the year.

Very surprised to learn that all 69's have 2" pipes. That's wierd to me.

Thanks again;

Stu Fox

Stu, Another Corvette exhaust story. My 68 Corvette 327/350 L79 came from the factory with 2 inch exhaust manifolds. The exhaust pipes were 2 inches at the connection point to the exhaust manifolds but a few inches from this connection point the exhaust pipes were 2 1/2 inches to the mufflers and factory installed.

[Joe L.]

Re: 69 L-89 Coupe

Stu, Another Corvette exhaust story. My 68 Corvette 327/350 L79 came from the factory with 2 inch exhaust manifolds. The exhaust pipes were 2 inches at the connection point to the exhaust manifolds but a few inches from this connection point the exhaust pipes were 2 1/2 inches to the mufflers and factory installed.

Jim------


All 1968 Corvettes were 2-1/2" exhaust, 300 hp to L-88. All small blocks after 1965 used 2" outlet manifolds. For applications with 2-1/2" exhaust the forward pipe was configured as you describe.

[Richard M.]

Re: 69 L-89 Coupe

Remember too that putting back undercar exhaust will increase interior heat.

Richard