What is the horse power ratings for all the C3 Years

 

Go here - http://www.idavette.net/facts.htm - Lots of facts to be found. :thumbs:

 

1968:
327ci/300HP
327ci/350HP
427ci/390HP
427ci/400HP
427ci/435HP
427ci/430HP (L88)

1969:
350ci/300HP
350ci/350HP
427ci/390HP
427ci/400HP
427ci/430HP (L88)
427ci/430HP (ZL1)
427ci/435HP

1970:
350ci/300HP
350ci/350HP
350ci/370HP (ZR1)
454ci/390HP

1971:
350ci/270HP
350ci/330HP (ZR1)
350ci/330HP (LT1)
454ci/365HP
454ci/425HP

1972:
350ci/200HP
350ci/255HP
454ci/270HP

1973:
350ci/190HP
350ci/250HP
454ci/275HP

1974:
350ci/195HP
350ci/250HP
454ci/270HP

1975:
350ci/165HP
350ci/205HP

1976:
350ci/180HP
350ci/210HP

1977:
350ci/180HP
350ci/210HP

1978:
350ci/175HP
350ci/185HP
350ci/220HP

1979:
350ci/195HP
350ci/225HP

1980:
305ci/180HP
350ci/190HP
350ci/230HP

1981:
350ci/190HP

1982:
350ci/200HP

That is per the Corvette Black Book.

 

why did the horse power drop in 74 is it because of emmissons control and what mods can be done to the stock motor to make have 300 horse power since it is a 350

 

In 1972 the horsepower numbers look lower...but they are actually very close to those in the 1970 and 1971 era. The reason the numbers are lower in 1972 is because the rating system was changed from Gross to Net horsepower.

1975 was the first year without the big block option and also the first year for the catalytic convertor. This was basically the beginning of the smog machines. Easy horsepower gains with the 1975-1982 cars could be had just by switching to a true dual exhaust.

 

Horsepower between 1974 and 1975 dropped due to emissions requirements...the cam profile was reduced, tuning was reduced, and exhaust was channeled through a single muffler with the edition of a catalytic converter. You can easily get the 195HP back to the 1974 standard by converting the exhaust to true duals with less restrictive exhaust. One option would be bying 2 high flow cats and 2 chambered mufflers and have them custom mounted along with a crossover tube for the air injection system. This would satisfy EPA requirements and keep it legal. The only reason for the single exhaust system was for expense. Back in 1975 the platinum coated catalytic converters cost about $500 each (that's none-adjusted...in adjusted dollars they would be about $2,000 each).

Of course you could just wait until the car is 30 years old and then convert it into an exhaust system that was used on one of the other year vettes...for example mine has the 1969 factory sidepipes.

 

Here in alabama there arent any emmissions control so i would not need cats but if were to put an exhaust on a 74 it would only still have 195hp

 

The L-48 are dogs for sure :smash: The first thing I would change would be the exhaust, get some headers, a crossover pipe (H or X pipe), 2.5" pipe, and some free-flowing mufflers, and get rid of the cats. Then I do would the cam, but since the carb and intake will be off to do the cam, you might as well do them all at once. The stock L-48's are in desperate need of a cam change :yesnod: . This is also a very good time to do the heads, if you have the money. AFR make the best heads, but Darts are pretty good too (and cheaper). If you really want to go nuts, you can pull the motor and put in a stroker kit and go to 383 or 388ci.

Here's some examples of motors I have saved on my Desktop Dyno.

-Dart Pro 1 aluminum 200cc heads
-Dual plane intake (I'd use the Edelbrock Performer RPM)
-750cfm carb (I'd use the Barry Grant Speed Demon)
-9.5:1 compression
-Small tube headers with mufflers
-Comp Cams XE270HR (roller) with .495"/.502" lift, and roller lifters
-350ci

This combo makes 425hp@6000rpm and 430ft/lbs@4500rpm
This same motor with the AFR 195cc competion heads makes 440hp@6000 and 435ft/lbs@4500
The cost to build would be a little less than $3k if you do it yourself

Here's the motor I'm building:

-388ci
-AFR 195cc competition package heads
-750cfm carb (I'll be using Speed Demon)
-Edelbrock Performer RPM intake
-10.5:1 compression
-Comp Cams Magnum 286HR (roller) with .560"/.560" lift
-complete roller valvetrain
-Large tube headers with open exhaust (side pipes)
-2* advance on the cam

This combo makes 505hp@6000 and 500ft/lbs@4500
This motor costs about $7k, but I'll be using a completely forged rotating assembly and a new block.

Good Luck, those late C3's can be turned into real performers with the right parts :cheers:

 

L48's of the same year compared to an L82 of that year, yes, maybe a dog. But look at say a 1975 L82(205hp) vs a 1979 L48(195). I just look at it this way: you can mod either and make great hp. L82 bottom end is nicer, but I've read in some SBC books that we shouldn't get too hung up on 4 bolt mains if you're not going for over 500hp.