Horsepower Guestimates
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Instructor
Joined: Apr 2004
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From: Manahawkin NJ
Horsepower Guestimates
On my 81 I desmogged it and But on a Torker II manifold (Clearance issues, don't ask), Edelbrock Performer Quadrajet 600Cfm ( or 650? Don't remember off the top of my head), New distributor and ignition system, and am looking into True Dual exhaust and Dyno Turbo Mufflers. I also removed the computer.
( i also redid the whole cooling system but that doesn't really matter.)
Do you think after all That work I'd be pushing 250+ Horse? I know the 81 was 190 stock.
(Forgive me if this is in the wrong forum because I'm still not sure on the forum switch, I think it's where it should be.)
( i also redid the whole cooling system but that doesn't really matter.)
Do you think after all That work I'd be pushing 250+ Horse? I know the 81 was 190 stock.
(Forgive me if this is in the wrong forum because I'm still not sure on the forum switch, I think it's where it should be.)
Race Director
Joined: Jan 2003
Posts: 15,175
Likes: 86
From: State of Confusion
Originally Posted by OneBrokenSmile07
Do you think after all That work I'd be pushing 250+ Horse? I know the 81 was 190 stock.
what you've done is made the icing and sprinkles without baking the cake.
Race Director
Joined: Jan 2003
Posts: 15,175
Likes: 86
From: State of Confusion
Originally Posted by OneBrokenSmile07
Do you think after all That work I'd be pushing 250+ Horse? I know the 81 was 190 stock.
what you've done is made the icing and sprinkles without baking the cake.
All of the above-stated modifications will REALLY wake-up with a camshaft and cylinder-head change, but until you change the valve-motion and compression ratio, you won't realize the full-potential of the intake/carb/ignition/exhaust:
did you run the car at a drag strip before making any changes?
The 'before' MPH, compared to the 'current' trap-speed may offer clues as to the HP-improvement.
Race Director
Joined: Jan 2003
Posts: 15,175
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From: State of Confusion
Originally Posted by ram82fire
Glen is quite right in his appraisal ,the cam and heads are the ticket to get the fuel air charge through the engine .
George!!!!!
Drifting
Joined: May 2003
Posts: 1,414
Likes: 2
From: Barrie
Originally Posted by OneBrokenSmile07
On my 81 I desmogged it and But on a Torker II manifold (Clearance issues, don't ask), Edelbrock Performer Quadrajet 600Cfm ( or 650? Don't remember off the top of my head), New distributor and ignition system, and am looking into True Dual exhaust and Dyno Turbo Mufflers. I also removed the computer.
( i also redid the whole cooling system but that doesn't really matter.)
Do you think after all That work I'd be pushing 250+ Horse? I know the 81 was 190 stock.
( i also redid the whole cooling system but that doesn't really matter.)
Do you think after all That work I'd be pushing 250+ Horse? I know the 81 was 190 stock.
Best way to find out HP is by running your car on the dyno.
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Race Director
Joined: Oct 2000
Posts: 15,009
Likes: 79
From: central FL, near the beach.
Originally Posted by OneBrokenSmile07
On my 81 I desmogged it and But on a Torker II manifold (Clearance issues, don't ask), Edelbrock Performer Quadrajet 600Cfm ( or 650? Don't remember off the top of my head), New distributor and ignition system, and am looking into True Dual exhaust and Dyno Turbo Mufflers. I also removed the computer.
( i also redid the whole cooling system but that doesn't really matter.)
Do you think after all That work I'd be pushing 250+ Horse? I know the 81 was 190 stock.
(Forgive me if this is in the wrong forum because I'm still not sure on the forum switch, I think it's where it should be.)
( i also redid the whole cooling system but that doesn't really matter.)
Do you think after all That work I'd be pushing 250+ Horse? I know the 81 was 190 stock.
(Forgive me if this is in the wrong forum because I'm still not sure on the forum switch, I think it's where it should be.)
Race Director
Joined: Apr 2000
Posts: 17,676
Likes: 201
From: Who says "Nothing is impossible" ? I've been doing nothing for years.
Big problem with the HP on stock C3's was the exhaust you put 2.5 in true dual exhaust without the cats, headers and good flowing ( read loud ) mufflers a you will be near 225HP with that alone, we are taliking flywheel/net HP here not rear wheel 
Melting Slicks
Joined: Jan 2004
Posts: 2,672
Likes: 1
From: New Cumberland PA
There was an old post, several years ago, that some one occassionally repost. It dealt with upgrading the exhaust to true duals, no cat's, and headers. The gain was over 50hp. So I would say you would be approaching 250hp. Size of the carb is not that big of a deal as the engine in general will limit the hp before the carb in a stock engine configuration. Tuning the carb for performance vs economy will have a greater effect than the size of the carb.
In my opinion, the exhaust system must be upgraded for any engine modifications. Changing cams, heads, etc will never realize their potential if the engine is unable to get rid of the exhaust effeciently.
In my opinion, the exhaust system must be upgraded for any engine modifications. Changing cams, heads, etc will never realize their potential if the engine is unable to get rid of the exhaust effeciently.
Pro
Joined: Aug 2002
Posts: 560
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From: The Valley of The Sun AZ
I think you guys are real optimistic about 230HP with exhaust/intake change. I think the 81 was optimistically rated at 190HP to begin with. I desmogged mine and went true duals and intake and while I did experience a SOTP change, 40HP it was not.
I would say at MOST 215HP, maybe less with the Torker II, it's not really the best flowing intake. Better than stock, but not as good as the performer.
To get HP out of the 81, you will NEED to do something with those heads and cam. While the 81 has some really good TQ for its time, it was still suffering from the 70's desmogging regulations.
I would say at MOST 215HP, maybe less with the Torker II, it's not really the best flowing intake. Better than stock, but not as good as the performer.
To get HP out of the 81, you will NEED to do something with those heads and cam. While the 81 has some really good TQ for its time, it was still suffering from the 70's desmogging regulations.
Instructor
Joined: Feb 2004
Posts: 241
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From: Ravenna Ohio
I have an 80 l-48. When i got it, it was bone stock except for true duals with glasspacks(gowf). I removed the AIR pump put on headers. I also got an underdrive pulley and a petronix dist. rebuild. The headers were very noticable mod.I layed down 180HP and 270TQ at the rear wheels. I only got it to the track twice last year for a total of 6 runs and with a slipping clutch i ran a 15.4 at 87mph. I actually spun and had smoke coming out of my clutch when i tried to brake torque it on a back road one day(tires did not spin only clutch i could hear it). I would say that with the new clutch i might be real close to 15 flat.
I'm putting on vortec heads and an intake and a cam i don't think there will be hood clearance either any ideas?
I'm putting on vortec heads and an intake and a cam i don't think there will be hood clearance either any ideas?
Melting Slicks
Joined: Jan 2004
Posts: 2,672
Likes: 1
From: New Cumberland PA
The biggest differences in engines from the 300+ horsepower for the late sixties and early seventies versus the mid year and newer is the heads and emmisions; and also they way they performed the test. The difference in horsepower over that span is well over 100. There is no way the just earlier heads were capable of that, although they did use different cams in the highest rated 350's. The main issuse was the exhaust; very restrictive. Take a look at the numbers and it easy to see that the later years peaked out much sooner in rpm's. The exhaust was the culprit which I do not think is debateable. It just wasn't capable of letting the engine breathe. Change the exhaust with duals, no cat's, and headers and it's better than the early C3's which had no headers. Change the cams, intake, and heads to something newer like vortecs and the late C3 will make more horsepower than the 330/350/370hp of the early models. This isn't rocket science, just going back and changing this to where they started at before emissions.
Race Director
Joined: Apr 1999
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From: CORVETTE 77 385 C.I. TEXAS
Originally Posted by mandm1200
There was an old post, several years ago, that some one occassionally repost. It dealt with upgrading the exhaust to true duals, no cat's, and headers. The gain was over 50hp. ...
http://www.corvettefaq.com/c3/ganeyexhaust.htm
