horsepower
Thread Starter
Heel & Toe
Joined: Sep 2011
Posts: 16
Likes: 0
horsepower
I am sure this question is asked all of the time, but I was wondering how to get more horsepower out of my 78 L48. I believe that it only has 190hp, which is okay, I did not buy it to race, but I would still like a little more. Is there any easy/inexpensive way to increase the hp, without altering the car's originality.
The car is completely original, and I don't really want to change that too much....
I just bought this car last week, and I love it. Its my 1st vette. I am new to the forum, it is great to get advise from other vette owners. I have posted a few other questions in the C3 General forum, and am greatful for all of the responses.
RV
The car is completely original, and I don't really want to change that too much....
I just bought this car last week, and I love it. Its my 1st vette. I am new to the forum, it is great to get advise from other vette owners. I have posted a few other questions in the C3 General forum, and am greatful for all of the responses.
RV
Instructor
Joined: Dec 2010
Posts: 106
Likes: 0
Drive it for 6 months before you decide to do anything. Enjoy it. Don't go tinkering until you've enjoyed it.
I have a '78 l48 as well.
You can't do much at all without altering the originality. The easiest things to do are:
- New carb, Holley
- Shortie headers ($300-500)
- new heads ($$$ expensive around $900-1300)
- New Holley Intake (around $200-300)
Just leave it be for a while. Come back in 6 months and ask again when you know more about the car
I have a '78 l48 as well.
You can't do much at all without altering the originality. The easiest things to do are:
- New carb, Holley
- Shortie headers ($300-500)
- new heads ($$$ expensive around $900-1300)
- New Holley Intake (around $200-300)
Just leave it be for a while. Come back in 6 months and ask again when you know more about the car
Le Mans Master
Joined: May 2002
Posts: 5,086
Likes: 786
From: Lebanon Township New Jersey
If the car still has the original type exhaust, get rid of the cat and convert to full dual exhaust with low restriction mufflers. Modify the advance curve in your distributor to get 36 deg, not counting vacuum advance, by about 2,500 rpm. These changes won't be visible and will noticeably improve performance. If your Quadrajet is working well, changing to a Holley won't help.
Race Director
Joined: Jan 2000
Posts: 12,399
Likes: 247
From: San Jose CA
If the car still has the original type exhaust, get rid of the cat and convert to full dual exhaust with low restriction mufflers. Modify the advance curve in your distributor to get 36 deg, not counting vacuum advance, by about 2,500 rpm. These changes won't be visible and will noticeably improve performance. If your Quadrajet is working well, changing to a Holley won't help.
Very good advice, and adding headers is worth a lot as well. You can have a very quick little car without opening the motor.
Thread Starter
Heel & Toe
Joined: Sep 2011
Posts: 16
Likes: 0
Guys,
Thanks for all of the input. I appreciate all of the replies. I will have to save a little more cash, and eventually make the proper up grades. I am having a lot of fun with the car as it sits. Hopefully the weather cooperates, and it will stay warm for another month or so. Ah! chicagoland weather. I will be storing it soon. A perfect time to work on it though.
Thanks for all of the input. I appreciate all of the replies. I will have to save a little more cash, and eventually make the proper up grades. I am having a lot of fun with the car as it sits. Hopefully the weather cooperates, and it will stay warm for another month or so. Ah! chicagoland weather. I will be storing it soon. A perfect time to work on it though.
Melting Slicks
Joined: Feb 2006
Posts: 2,209
Likes: 0
From: Mo
i would get a edelbrock performer rpm top end kit, (heads, cam, intake, carb) and put it on it, add some good headers(long tube) good exhaust with a min of 2.5 inch pipes. i prefer flowmaster mufflers. all this will put you in the 400 range.
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Safety Car
Joined: Oct 2000
Posts: 3,593
Likes: 103
From: Southern Indiana
Wow what a lot of "wrong" info here!
1:
Not on a 8.5 comp engine, you will be lucky to hit 300 horse.
2:
Shortie headers are useless and a good intake only cost maybe $140.
3"
A Holley is a positive over any quadrajunk anyday that ends in a "Y"
1:
this will put you in the 400 range.
2:
- Shortie headers ($300-500)
- New Holley Intake (around $200-300)
- New Holley Intake (around $200-300)
3"
If your Quadrajunk is working well, changing to a Holley won't help.
Race Director
Joined: Apr 1999
Posts: 11,520
Likes: 13
From: CORVETTE 77 385 C.I. TEXAS
Other things can be easily reversed like a low restriction cat or a pipe instead & low restriction mufflers. See what many refer to as my Exhaust topic.
http://www.corvettefaq.com/c3/ganeyexhaust.htm
Rear gears are good for manual & a higher stall converter works for auto.
Race Director
Joined: Nov 2002
Posts: 12,142
Likes: 54
From: Taylor Michigan
a GM 151 hydraulic lifter camshaft that is used in the 350 HP 327`s and a set of LT-1 valve springs will improve the performance without changing the other components.........and very compatible with a automatic or 4 speed........nothing wrong with a good Q-jet either......so leave it alone.....
AEKDB
AEKDB
Drifting
Joined: Mar 2011
Posts: 1,886
Likes: 9
A Quadrajet is a very sophisticated carb, and not everybody knows how to fix it. Parts are a bit harder to get than Holley. Every speed shop in the country stocks parts for Holley.
But if a Qjet is set up correctly, it will run like a champ. Do not think of it as a liability. It's a fine piece of equipment.
But if a Qjet is set up correctly, it will run like a champ. Do not think of it as a liability. It's a fine piece of equipment.
Safety Car
Joined: Oct 2000
Posts: 3,593
Likes: 103
From: Southern Indiana
A Quadrajet is a very sophisticated carb,
and not everybody knows how to fix it.
Parts are a bit harder to get than Holley.
Every speed shop in the country stocks parts for Holley.
But if a Qjet is set up correctly, it will run like a champ.
Do not think of it as a liability.
It's a fine piece of equipment.
There junk.
They are marginal for something stock.
You shouldn't have to rebuild the whole thing just to upgrade the rest of the engine.
With a Holley you just slap it on there and adjust the floats and air bleeder screws and close the hood, if you can't do that stick with a stock engine and a Quadrajunk.
Last edited by Tim H; Sep 23, 2011 at 06:04 PM.
Le Mans Master
Joined: Mar 2008
Posts: 5,948
Likes: 72
From: Oxford MA-----You just lost the game!!!!
A Quadrajet is a very sophisticated carb, and not everybody knows how to fix it. Parts are a bit harder to get than Holley. Every speed shop in the country stocks parts for Holley.
But if a Qjet is set up correctly, it will run like a champ. Do not think of it as a liability. It's a fine piece of equipment.
But if a Qjet is set up correctly, it will run like a champ. Do not think of it as a liability. It's a fine piece of equipment.
Scott
Le Mans Master
Joined: Mar 2008
Posts: 5,948
Likes: 72
From: Oxford MA-----You just lost the game!!!!
If the car still has the original type exhaust, get rid of the cat and convert to full dual exhaust with low restriction mufflers. Modify the advance curve in your distributor to get 36 deg, not counting vacuum advance, by about 2,500 rpm. These changes won't be visible and will noticeably improve performance. If your Quadrajet is working well, changing to a Holley won't help.
Might I add that you can find Edelbrock 2101 intake manifolds on ebay and craigs list for less than 50 bucks. I also agree with keeping the Q-jet if it runs well. They are great carbs, I just wish someone made metering rods for 'em.
Scott
Safety Car
Joined: Oct 2000
Posts: 3,593
Likes: 103
From: Southern Indiana
Let me sing a different note.
I understand lots of people have to run a Quad because thats what is on their car and /or it runs just fine.
But if you start upgrading cams, heads, ETC no matter what you do to a quad or how much money you pour into one, a Holley is going to out preform it hands down.
I have built a real good quad one time and had the best parts and main body and it even idled with a big cam.
I started to compare it with a Holley 750 Vacuum secondary and I knew right them I wasted a whole lot of money on a quadrajunk.
So do you own comparison and pick what runs best for you.
I understand lots of people have to run a Quad because thats what is on their car and /or it runs just fine.
But if you start upgrading cams, heads, ETC no matter what you do to a quad or how much money you pour into one, a Holley is going to out preform it hands down.
I have built a real good quad one time and had the best parts and main body and it even idled with a big cam.
I started to compare it with a Holley 750 Vacuum secondary and I knew right them I wasted a whole lot of money on a quadrajunk.
So do you own comparison and pick what runs best for you.