1967 427 Corvette on The Dyno, Sidepipes KILLED Horsepower! C2 Mid-Year Vette Gains 48 RWHP! 

What a beauty. 1967 was such a great year for automobile design.

Headers with 2 1/2" exhausts

C2 coupes are total dream corvettes!!! I love every chance I get to see one!!!!!!

I had a B&M 144 blown 350 chevy motor and had hooker side pipe headers. When I had the glass pack mufflers it ran great. I bought a set of turbo mufflers for the hooker side pipes. When I bolted them on I swore I somehow knocked of a couple of plug wires the HP drop was so bad. So yes a bad exhaust can kill your HP.

it’s pretty cool watching you improve the tune on this car little by little! it would be so addicting to keep trying things. looking forward to watching you find the peak.

67 is the coolest Corvette, bar none.

Imagine buying a brand new Corvette with sidepipes in 67 and lining up against a friend with a non sidepipe car. I think there would be some angry words at the dealership the next day.

I know I'm late to the party but... yeah, those side pipes look cool and sound even cooler, but they're no good for power. The stock "out the back" pipes were actually better flowing. However, just running open manifolds isn't the best way to make power either, you need about a foot of pipe added on to the manifolds to get the most out them. If you are required to run a "full exhaust system", look for a set of factory header side pipes... Chevy actually offered them as a dealer installed option back in the day, and reproductions are still available. Oh, and you need 4.11 gears in that thing... 3.30s are for road racing and fuel economy. LOL

Run those side pipes with long tube headers and watch what happens.

No doubt! Had a buddy hang a set on his 'stang...total power loss that grew as he pushed up the tac...

My kinda guys. I hope to run my 63 soon broke the axle shafts first trip to the track. We run 1/8 round here. Hopin for high 7 sec range.

If ya like sidepipes, then good enough

My Uncle had a 67 Corvette with a 435 hp 427. My Dad would always take it home from our shop on Friday and go out looking for races on Friday nights. We had a few Corvette’s over the years but Camaro’s and Nova’s were our favorites.

I'll happily sacrifice a little bit of power for the glorious sound side pipes make :P

Those engines were technically built to run on leaded 101-105 octane pump gas in 67'. The best you can get now is unleaded 91-93 octane.

I really enjoy your videos. Thanks.

Excellent comparison with side exhausts.I'm from back in the day and not that many 1965-67s came with them- they are mostly added on these days. Seeing them on 1963 and 1964s looks silly as they were not an option until 1965. I NEVER LIKED THEM, stepping over them and they make the car look cluttered and 'rob horsepower' thanks for proving my point about power robbing. To each their own. Have fun with whichever you want. Back in the 60s most vettes were daily drivers, mine was, all seasons. That was quite normal back then.

Love the color too

Great video and the pic of the 67 running against Donny and his 66 is killer

My favourite Vette, C2 1963-67 Stingray Coupe.

Solder up the jets and re bore them.

Love the 67 C2 coupés, but give me a 327/350 any day for driving.

Love watching the Dyno vids and all the small improvement to make HP.

I never have liked side pipes. What if you guys ditched the tri-power?

I had said the side pipes ROB hp , Thanks for the video

Fun stuff, everyone should have a DIY home dyno. Hard telling without seeing the exhaust but... can't you cut out the crimped/restrictive pipe section and replace it with some full 2 1/2" (if it would mount behind the side pipe shield)?

13.1 damn! congrats. Nice job.

the window track is not a door handle

That's bad ass. I love vettes.

According to Babvvo and Tebbvo laws, sadly soon all combustion cars and trucks including classics will be banned from public streets in entire EU and Scandinavia :-( In Germany the Green Peoples Party gave order to shorten fuel supply from 2025 on by reducing all conventional fuel stations to only one state operated central gas station per city or county. Car washs will be forbidden too because they are climate killers, now they want to slow down all the gas station pumps from 20 litre per minute to 2 litre per minute...From 2027 on in the EU certain car spare parts will be banned too....as exhaust systems, turbo chargers and even some engine and gearbox oils...California and New York will do the same from 2027 on.... So no investments should be done in oil burning cars any longer....They even created a new kind of crime here, called emissions and smoke crime!!!

Know a guy who bought a 69 390 horse brand new with side pipes. People asked him the next day how it ran. He told them "It will go clean outta numbers" don't think the 69 side pipes were holding anything back.

That Car is Beautiful

run the side pipe fender well exit headers that come out the side the Roadster header mufflers that's where you have your biggest gain out the inch and 7/8 primaries into a 3-inch collector in a 3-inch Muffler side pipe exit

All good, except the real advantage of the side pipes was to reduce the in-cabin heat. The standard pipes ran along the trans tunnel next to your leg. You really don't want that, believe me, with a big block on a warm day. Or any day, really.

The 67vette and 67 Ferrari 250 GTO are the greatest sport cars ever made.

Do they bigger diameter side pipes on early C3's lose power as well?

OK so make the short drive to PSMCDR and join us! Like how you're keeping this one simple/stock Jordan.

Horsepower isn’t everything, sometimes style points come into play.

I’d like to see it with the full exhaust the intake ported and a real set of carbs

Any backpressure is no good

I have a 406 small block in my c3 that has 2x+ that first hits HP NA though. But my heads flow 315cfm at .600 lift and that helps.

Maybe this is a dumb question. Could you run a straight pipe bent to mimic the side pipe or are mufflers required?

We knew back then that side exhaust was a horsepower killer, but we thought they were cool. If we wanted real power we changed them out to something more conducive to high power.

Man, I'd love to see someone doing some serious work with a DZ 302 , or a 1970 350 LT1 .. oneday perhaps . Hey I've had good luck with those Black Widow mufflers from Jeg's . They actually have a model called the 'NeighbourHater' which I thought was LOLMAO

Classic chambered has the bigger inner diameter sidepipes/mufflers you need.

Hey I am thinking could you make these side pipes look stock without baffles?

any altercation to factory exhaust cuts power and mileage

Could you fabricate a set of 3"-3 1/4" straight pipes? Would they fit under the heat shields? Really enjoy your videos. The 67 was always my favorite!!! Do they make baffles that would fit inside the pipes like on motorcycles?106 ain't to shabby for a 400 HP Vette! Nice run!

Is this car a 400 or 435 hp?

What vehicle from 1967 WASNT cool looking? they had so much style back then.

Of course side pipes killed horsepower but it was all about the sound

That's a pretty good gain in the horsepower just saying

Thats it? these 427s should have made atleast 430hp and revved to atleast 6k

So it lost 100 hp 80-100 that's about right so it might make 400 or close at the crank one big Holley would make more power 6 inch tire lol

Couldn't you have brazed a set of jets closed then drilled them smaller? Or is that not allowed?

Did removing the exhaust help the mixture to get a little less rich, you did not say

Dang, MEAN C2!

Yep. The factory side pipes are extremely restrictive, and poorly tuned. Throw on a set of the old Hooker 4 into 1 side pipe headers.

Damn! how much do these cars weigh!

What are the "certain mufflers" that cost you HP? Are they a sponsor or something? I don't want to make that mistake on my street car.

Did opening up the exhaust lean out the afr?

No need to maximize horsepower on this car. Get smooth idle and transition and drive it. Big block. Done.

Advertised 425 hp should put at least 350 to the rear wheels

Put 4:56's in the ass end and you'll cut your ET by a huge margin. But of course, you know that. But Green Who the fk would paint a 427 Vette green? Yuck.

the 67 427 had 435 hp.

Need 456 rear gear

long tube large diameter tube headers nutn' less

I gave up after you started a dyno test with knowing where the timing is too bad you did not detonate the enine and kick a rod- maybe you learn something.

Why don't you just run open pipes right thru and out the side pipe spots?? If you want "mufflers just put some glass packs in the side pipe slots!!

Salut my friend super car super video subscribe subscribe