1975
Thread Starter
1st Gear
Joined: Oct 2008
Posts: 1
Likes: 0
1975
I have purchased a nice clean 1975 corvette. I understand that because this was the first year to have the emmission system the engine doged down to 204 hp or so.
My question is if this is the case could i remove the exhaust with cadiliac converters and other emission stock items and make this car fly???
My question is if this is the case could i remove the exhaust with cadiliac converters and other emission stock items and make this car fly???
Instructor
Joined: Mar 2008
Posts: 132
Likes: 0
From: Corona CA
Well taking off the emissions junk definitely can't hurt with regards to HP. That being said taking it off will hurt the originality of the car (if you care about that). I don't know how much HP you will gain but would imagine someone will respond soon with that info.
Have fun with your vette
Have fun with your vette
Drifting
Joined: Sep 2006
Posts: 1,259
Likes: 2
From: MS
Yes, the original style catalytic converters used in the 70's were the worst ever for performance,
and a more free flowing exhaust system would definitely add power.
Comparing the 74 (true duals, no cat) to the 75 you can see the difference and there is still more power to be made,
...........74...........75
L48....195hp.......165hp
L82....250hp.......205hp
The 165hp on the 75 L48 was the lowest rated V8 horsepower in Corvette history.
and a more free flowing exhaust system would definitely add power.
Comparing the 74 (true duals, no cat) to the 75 you can see the difference and there is still more power to be made,
...........74...........75
L48....195hp.......165hp
L82....250hp.......205hp
The 165hp on the 75 L48 was the lowest rated V8 horsepower in Corvette history.
Drifting
Joined: Jan 2005
Posts: 1,438
Likes: 3
From: Florissant MO
As said, unless you want to keep it original -
Trash the Y pipe & cat.
Get a manifold back true dual exhaust 2.5" system.
You will have a noticeable seat of the pants difference immediately.
Once you have done that, trash the boat anchor of an intake and put on a good Edelbrock or equivalent. You will feel some more seat of the pants difference, but not as much as with the exhaust.
When I use the word "trash" don't really throw them out, put them up in a nice safe place in the rare case of you wanting to go back to original.
Trash the Y pipe & cat.
Get a manifold back true dual exhaust 2.5" system.
You will have a noticeable seat of the pants difference immediately.
Once you have done that, trash the boat anchor of an intake and put on a good Edelbrock or equivalent. You will feel some more seat of the pants difference, but not as much as with the exhaust.
When I use the word "trash" don't really throw them out, put them up in a nice safe place in the rare case of you wanting to go back to original.
Last edited by 75 Red Vert; Oct 3, 2008 at 04:25 PM.
Burning Brakes
Joined: Feb 2003
Posts: 1,128
Likes: 4
From: Upland Ca
Removal of the equipment really depends on where you live. For instance if you lived in Cali your 75 would be exempt from the bi-annual smog checks but you still have to keep the car legal. If stopped for anything they could cite you for lack of smog equipment. As far as "flying" with out the smog stuff, don't hold your breath. The few ponies you'll pick up with free flowing exhaust will hardly be felt on top of that rocket 165HP L48 or even the 205HP L82, the compression is just to low to build any real HP.
Safety Car
Joined: Aug 2001
Posts: 4,883
Likes: 11
From: North Easton Mass
I have purchased a nice clean 1975 corvette. I understand that because this was the first year to have the emmission system the engine doged down to 204 hp or so.
My question is if this is the case could i remove the exhaust with cadiliac converters and other emission stock items and make this car fly???
My question is if this is the case could i remove the exhaust with cadiliac converters and other emission stock items and make this car fly???
Rick B.
Burning Brakes
Joined: Aug 2007
Posts: 792
Likes: 4
From: New Jersey
As you already know - the '75 vert was the last convertible until '86 and the last C3 verts. Therefore, depending on your serial number and options, you car might be more valuable if you leave it stock or at least keep any parts you remove from it. I also have a '75 vert with a VERY low serial number and a letter from St Louis plant stating that it was one of the first of the '75 model year to be sold to the public...does it make it worth more - only to me I guess.
Good luck with your vert and I hope you enjoy it as much as I have enjoyed mine for the last 34 years (got mine in Oct '74).
Good luck with your vert and I hope you enjoy it as much as I have enjoyed mine for the last 34 years (got mine in Oct '74).
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
Top 10 Corvette Engines RANKED by Peak Torque (70+ Years of Muscle!)
Joe Kucinski
Corvette ZR1X Will Be Pacing the Indy 500, And Could Probably Race, Too!
Verdad Gallardo
Top 10 Corvettes Coming to Mecum Indy 2026!
Brett Foote
Top 10 C9 Corvette MUST-HAVES to Fix These C8 Generation Flaws!
Michael S. Palmer
10 Revolutionary 'Corvette Firsts' Most People Don't Know
Joe Kucinski
5 Reasons to Upgrade to an LS6-Powered Corvette; 5 Reasons to Stay LT2
Michael S. Palmer
2027 Corvette vs The World: Every C8 vs Its Closest Competitor
Joe Kucinski
10 Most Common Corvette Problems of the Last 20 Years!
Joe Kucinski
