Help Info With Engine
Thread Starter
Racer
Joined: Jul 2001
Posts: 311
Likes: 0
From: St. Amant LA
Help Info With Engine
Hi, I purchased a 1977 C3 vette late last year. They owner didnt know much about the engine because he had just purchased it from a guy who was restoring it and then in turn sold it to me to buy a 65 vette. I am only 16 and dont know much about engines yet. I want more power so I was thinking of getting new heads and cam...however my mechanic said I had a 268 cam which was good enough....so I guess ill just get new heads. I am looking at the TFS 23 Degree heads to put on it. All I know about the engine is its a 350 and seems to be new and I do not think its original. It doesnt seem to have much power either as I cant chirp out or anything really. Any help would be appreciated.
Race Director
Joined: Jan 2000
Posts: 12,399
Likes: 247
From: San Jose CA
Re: Help Info With Engine (C3Vettesrock)
If it's an automatic, it's difficult to chirp out. I don't know how the mechanic knew that you had a 268H cam in there, but if you do, it's a very good cam. TFS 23 degree heads run very well, AFRs are worth about 20 hp over the TFS heads though. If the engine has stock heads, you're probably looking at about a 40-60 hp jump with the change.
It's easy to chirp the tires in my car, and I have an automatic transmission w/ stock engine. If your car is automatic, a brake stand should do the trick. If you don't know what a brake stand is, basically apply the brakes to keep the car from rolling and apply the gas up to whatever speed you feel would give you an appropriate launch. Not good for the master cylinder, but performance driving is hardly ever good for any part of the car.
I'm 18, got my 'vette when I was 16. If you have AIM, you can IM me: BreakManX2. My ICQ UIN is 367029. I know a decent amount about modifying 350s, but I'm nowhere near as knowledgeable as a lot of people here (Ganey, Chuck Harmon, GKull, GDaina, etc...)
-Steve
It's easy to chirp the tires in my car, and I have an automatic transmission w/ stock engine. If your car is automatic, a brake stand should do the trick. If you don't know what a brake stand is, basically apply the brakes to keep the car from rolling and apply the gas up to whatever speed you feel would give you an appropriate launch. Not good for the master cylinder, but performance driving is hardly ever good for any part of the car.
I'm 18, got my 'vette when I was 16. If you have AIM, you can IM me: BreakManX2. My ICQ UIN is 367029. I know a decent amount about modifying 350s, but I'm nowhere near as knowledgeable as a lot of people here (Ganey, Chuck Harmon, GKull, GDaina, etc...)
-Steve
Race Director
Joined: Jan 2000
Posts: 12,399
Likes: 247
From: San Jose CA
Re: Help Info With Engine (C3Vettesrock)
Also, do you know if the engine in your car was an L48 or an L82? L82 is indicated by higher redline. The yellow line on an L48 starts at the low-5000s.
L82 idles higher as well. I don't know the cosmetic differences between L48 and L82 in a 77, however... only 78.
Good luck with it.
-Steve
L82 idles higher as well. I don't know the cosmetic differences between L48 and L82 in a 77, however... only 78.
Good luck with it.
-Steve
Le Mans Master
Joined: Feb 2000
Posts: 7,032
Likes: 2
From: Newburgh NY
Re: Help Info With Engine (C3Vettesrock)
C3, check this link out to learn about where the engine number are located. If you can find and read them, post them here and we'll decipher them for you. Also, you can tell by the VIN number.
If the 5th digit in the VIN is an "L", it was originally an L48.
If the 5th digit in the VIN is an "X", it was originally an L82.
Now you just need to see if it's still the original or engine you have there.
Check this out.
http://www.sharkwerkes.com/sharktank.../vinguide.html
If the 5th digit in the VIN is an "L", it was originally an L48.
If the 5th digit in the VIN is an "X", it was originally an L82.
Now you just need to see if it's still the original or engine you have there.
Check this out.
http://www.sharkwerkes.com/sharktank.../vinguide.html
Race Director
Joined: Apr 1999
Posts: 11,520
Likes: 13
From: CORVETTE 77 385 C.I. TEXAS
Re: Help Info With Engine (C3Vettesrock)
Mike
1) Do you have L-82 on the hood ? Check VIN as described above.
2) Why does mechanic think you have a 268H cam? Check w/ previous owner for cam & other mods. How is idle- smooth or lopey?
Evidently you have an auto. since all you have to do w/ a manual is wind it up & drop the clutch.
3) What is exhaust? See: Why Exhaust is problem for HP on 75-81 http://www.corvetteforum.cc/ubb/Foru...ML/008082.html
Set initial timing to 12-16 BTDC & recurve dist. to about 36 total all in by 1800-2800 rpm.
:cool:
1) Do you have L-82 on the hood ? Check VIN as described above.
2) Why does mechanic think you have a 268H cam? Check w/ previous owner for cam & other mods. How is idle- smooth or lopey?
Evidently you have an auto. since all you have to do w/ a manual is wind it up & drop the clutch.
3) What is exhaust? See: Why Exhaust is problem for HP on 75-81 http://www.corvetteforum.cc/ubb/Foru...ML/008082.html
Set initial timing to 12-16 BTDC & recurve dist. to about 36 total all in by 1800-2800 rpm.
:cool:
Thread Starter
Racer
Joined: Jul 2001
Posts: 311
Likes: 0
From: St. Amant LA
Re: Help Info With Engine (C3Vettesrock)
Its a l48 but the engine isnt original to my knowledge, the owner before me didnt know much about the engine besides it looked new. I have hooker sidepipes on it, ill get a picture of the engine.
Thread Starter
Racer
Joined: Jul 2001
Posts: 311
Likes: 0
From: St. Amant LA
Re: Help Info With Engine (C3Vettesrock)
The idle sounds lopey and it is a L48, holley 650 carb, automatic transmission. If any of that helps...
Any more info needed let me know, I want this thing to run pretty well
Any more info needed let me know, I want this thing to run pretty well
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Race Director
Joined: Apr 1999
Posts: 11,520
Likes: 13
From: CORVETTE 77 385 C.I. TEXAS
Re: Help Info With Engine (C3Vettesrock)
Set the timing as above. Power braking is not hard or bad for the master cylinder. Power brake & see what rpm you are at & launch then notice if it goes immediately or if accel. slowly then what rpm it takes off at.
Intermediate
Joined: Aug 2001
Posts: 36
Likes: 0
From: Jacksonville, FL
Why do you need more power?
Mash the gas all the way to the floor. It'll build more power than you need. After the tires advance beyond chirping, they'll have very little traction. When your 'Vette swaps ends, close your eyes and pray. If you're still not happy, pour clorox on the road. That will really impress your friends.
Hi-Po heads, cams etc. don't make horsepower until the RPMs are way up there. By that time, you're at the next redlight and need to stop. Focus on low end torque. You need to get that car rolling and accelerating from 1000 to 2500 rpm. That's what torque does.
Chirping tires rub a little bit of rubber off each time. After a few times, they're out of balance. After a bunch of times, they can be thrown away. Chirping tires also have less traction. You don't want the tire to chirp, you want it to grip. You don't want you power wasted in spinning the trie, you want it moving the car forward.
Hi-Po heads, cams etc. don't make horsepower until the RPMs are way up there. By that time, you're at the next redlight and need to stop. Focus on low end torque. You need to get that car rolling and accelerating from 1000 to 2500 rpm. That's what torque does.
Chirping tires rub a little bit of rubber off each time. After a few times, they're out of balance. After a bunch of times, they can be thrown away. Chirping tires also have less traction. You don't want the tire to chirp, you want it to grip. You don't want you power wasted in spinning the trie, you want it moving the car forward.
Drifting
Joined: Sep 2000
Posts: 1,616
Likes: 2
From: Round Rock, Texas, USA Texas
Re: Help Info With Engine (C3Vettesrock)
You might want to take a look at the other end - the '77 L48 probably came with 3.08 rear gears. Mine already had 3.55's in it when I got it and it has plenty (okay enough for me - for now) seat of the pants tire chirping performance. :D