75 L48 beef up ideas?
Thread Starter
Le Mans Master
Joined: Jul 2006
Posts: 5,894
Likes: 1
From: Farmingdale NY
St. Jude Donor '06
75 L48 beef up ideas?
New to this forum and looking for some ideas to beef up a 75 L48.
I just got the car, it’s a little rough but all there and looks to have never been apart. It’s going to be my winter project. First Vette in 30 years.
It’s a numbers matching 75 coupe with L48 and 4 Spd. I got it because I love the body style, but I hate the lack of power. Not looking to hot rod the car, but I would like to have a little more power.
I want to keep the engine compartment as stock appearing as possible and would like to stay with the Q-Jet so I can keep the original air cleaner. I have no problem swapping out the heads, intake, cam, etc..
I’m also looking to upgrade the exhaust, but want to keep the exhaust manifolds.
Any ideas?
Thanks in advance.
I just got the car, it’s a little rough but all there and looks to have never been apart. It’s going to be my winter project. First Vette in 30 years.
It’s a numbers matching 75 coupe with L48 and 4 Spd. I got it because I love the body style, but I hate the lack of power. Not looking to hot rod the car, but I would like to have a little more power.
I want to keep the engine compartment as stock appearing as possible and would like to stay with the Q-Jet so I can keep the original air cleaner. I have no problem swapping out the heads, intake, cam, etc..
I’m also looking to upgrade the exhaust, but want to keep the exhaust manifolds.
Any ideas?
Thanks in advance.
Advanced
Joined: Aug 2005
Posts: 50
Likes: 0
From: Michigan
Crate motor.
Seriously, I don't see the point in 'improving' an unmolested original motor, and i can't see how you'll get more hp while keeping it looking stock. The things you list make sense - better breathing would always be first on my list - but if you leave the manifolds alone I don't see much point in replacing the exhaust.
Just my $0.02.
Seriously, I don't see the point in 'improving' an unmolested original motor, and i can't see how you'll get more hp while keeping it looking stock. The things you list make sense - better breathing would always be first on my list - but if you leave the manifolds alone I don't see much point in replacing the exhaust.
Just my $0.02.
Thread Starter
Le Mans Master
Joined: Jul 2006
Posts: 5,894
Likes: 1
From: Farmingdale NY
St. Jude Donor '06
Motor
The motor is original and tired. It is coming out this winter for a re-build anyway. I figure that as long as it has to come apart, why not beef it up just a little bit. The block will still be used, and I will put the heads and intake on the shelf.
I was thinking that a true dual exhaust will be an improvement over whats there, but I'm not up on what systems are out there now for Vettes. The exhaust needs replacing anyway.
I was thinking that a true dual exhaust will be an improvement over whats there, but I'm not up on what systems are out there now for Vettes. The exhaust needs replacing anyway.
Thread Starter
Le Mans Master
Joined: Jul 2006
Posts: 5,894
Likes: 1
From: Farmingdale NY
St. Jude Donor '06
Manifolds
Originally Posted by Nemesis_152
for a stock looking vehicle, why not get some better flowing factory-style manifolds, or port your existing manifolds. heads, cam, intake, and that could net you close to 300 with stockish manifolds, i would think.
It doesn't have to be perfectly stock I just don't want headers, and would like to keep using the stock air cleaner, etc..
I was thinking that the cost for the machine work on the stock heads and intake wouldn't be worth it and that I might be able to get a better set of heads to start out with and maybe go for an aftermarket manifold that the Q-Jet would work with. Putting away an original set of heads and intake is not the end of the world.
The better flowing, stock appearing exhaust manifolds are an interesting idea though! Any suggestions on what to look for? Aftermarket?
My other car is a GTO and I'm much more aware of the Pontiac stuff out there.
This is the first Chevy in 30 years, and I am not up on whats out there.
Melting Slicks
Joined: Mar 2006
Posts: 3,342
Likes: 7
From: Connecticut
Just leave it alone
They arent 400HP but they go pretty good
If you want to race around town buy an ald Camaro, Chevelle ect:
And it wont cost much more than an engine upgrade for The Corvette
You can bastardize a camaro, chevelle nova Elcamino all you want but...
The Vette still gets the all looks
They arent 400HP but they go pretty good
If you want to race around town buy an ald Camaro, Chevelle ect:
And it wont cost much more than an engine upgrade for The Corvette
You can bastardize a camaro, chevelle nova Elcamino all you want but...
The Vette still gets the all looks
Last edited by Bob Onit; Jul 22, 2006 at 07:20 PM.
Melting Slicks
Joined: Dec 2000
Posts: 3,407
Likes: 2
From: Carmichael CA
Your most HP for the buck is exhaust. The OEM ram style exhaust manifolds are fine. Mine is a stock L48 and I get 200HP at the rear wheels which is about 60HP over stock...the only change was the sidepipes which are a chambered exhaust system. When I was looking at rebuilding my engine I looked around at cam shafts and the Comp Cams 268H looked like a winner, though some of the other folks here will rightfully say that the 262XE is a better cam. They both will give you an extra 50HP. In order to get more HP than the extra 110 you would get with exhaust and cam swap you will be looking at new heads and those won't come cheap and you may need to get a different intake manifold if you get the new vortec heads since the bolt holes won't match up with your stock manifold. If you do the exhaust, cam, and heads you will be getting around 300HP at the rear wheels.
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Pro
Joined: Jan 2006
Posts: 548
Likes: 0
Originally Posted by Bob Onit
Just leave it alone
They arent 400HP but they go pretty good
If you want to race around town buy an ald Camaro, Chevelle ect:
And it wont cost much more than an engine upgrade for The Corvette
You can bastardize a camaro, chevelle nova Elcamino all you want but...
The Vette still gets the all looks
They arent 400HP but they go pretty good
If you want to race around town buy an ald Camaro, Chevelle ect:
And it wont cost much more than an engine upgrade for The Corvette
You can bastardize a camaro, chevelle nova Elcamino all you want but...
The Vette still gets the all looks
165hp was an embarrasment to the corvette name...it would be almost better to up that to drown out some of the shame the l48 brought.
Drifting
Joined: May 2005
Posts: 1,629
Likes: 4
From: Somers CT
I went thru the same thing with mine trying to figure the best route, buy some parts to tide me over for a while, rebuild the motor, or buy a crate.
I ended up buying a crate motor and what convinced me was pulling a valve cover one day to fix an oil leak. My car had 60K at the time but looking at the oil sludge baked on the heads and valve covers convinced me spending a bunch of money on a 30 year old engine was not the best thing. Putting high compression heads on pistons with tired rings and bearings is asking for trouble in my opinion.
I'm happy with the choice I made and it was the cheaper way to go for me.
Why don't you want headers??? I put ceramic ones on and they made a significant difference in reducing the heat both under the hood and in the cabin. Bolted right up with no problems.
Good luck with whatever you choose
Bill
I ended up buying a crate motor and what convinced me was pulling a valve cover one day to fix an oil leak. My car had 60K at the time but looking at the oil sludge baked on the heads and valve covers convinced me spending a bunch of money on a 30 year old engine was not the best thing. Putting high compression heads on pistons with tired rings and bearings is asking for trouble in my opinion.
I'm happy with the choice I made and it was the cheaper way to go for me.
Why don't you want headers??? I put ceramic ones on and they made a significant difference in reducing the heat both under the hood and in the cabin. Bolted right up with no problems.
Good luck with whatever you choose
Bill
Last edited by TopGunn; Jul 22, 2006 at 08:57 PM.
Melting Slicks
Joined: Mar 2006
Posts: 3,342
Likes: 7
From: Connecticut
I was speaking about spending big $ on a crate engine or custom built..
My L48 has about 7 or 8 K miles on a rebuild and it is very clean inside
I had weighed the options of a crate engine or new heads/cam shaft, ect on the L48 but @ 190HP it goes ok
If I want to scream around town Ill drive my 70 ElCamino SS LS-6 Just my opinion
If you decide to alter the L48 just make sure you keep all the original parts
My L48 has about 7 or 8 K miles on a rebuild and it is very clean inside
I had weighed the options of a crate engine or new heads/cam shaft, ect on the L48 but @ 190HP it goes ok
If I want to scream around town Ill drive my 70 ElCamino SS LS-6 Just my opinion
If you decide to alter the L48 just make sure you keep all the original parts
Thread Starter
Le Mans Master
Joined: Jul 2006
Posts: 5,894
Likes: 1
From: Farmingdale NY
St. Jude Donor '06
I am pulling the motor out in the fall. I intend to rebuild the short block anyway. I thought it was a good chance to get some better heads, cam, intake, etc..
I would like to find better flowing exhaust manifolds and run a nice true dual exhaust (2 1/2").
I know that with the GTO's that the Ram Air manifolds are much better than the stock ones, and there are companies out there that make them re-production and you can order them ceramic coated. You can also get complete 2 1/2" mandrel bent exhaust systems ready to bolt in. I was just wondering if the same exhaust options were available for the Corvettes.
I'm not a big fan of headers.
I would like to find better flowing exhaust manifolds and run a nice true dual exhaust (2 1/2").
I know that with the GTO's that the Ram Air manifolds are much better than the stock ones, and there are companies out there that make them re-production and you can order them ceramic coated. You can also get complete 2 1/2" mandrel bent exhaust systems ready to bolt in. I was just wondering if the same exhaust options were available for the Corvettes.
I'm not a big fan of headers.
Pro
Joined: Jan 2006
Posts: 548
Likes: 0
Originally Posted by Bob Onit
I was speaking about spending big $ on a crate engine or custom built..
My L48 has about 7 or 8 K miles on a rebuild and it is very clean inside
I had weighed the options of a crate engine or new heads/cam shaft, ect on the L48 but @ 190HP it goes ok
If I want to scream around town Ill drive my 70 ElCamino SS LS-6 Just my opinion
If you decide to alter the L48 just make sure you keep all the original parts
My L48 has about 7 or 8 K miles on a rebuild and it is very clean inside
I had weighed the options of a crate engine or new heads/cam shaft, ect on the L48 but @ 190HP it goes ok
If I want to scream around town Ill drive my 70 ElCamino SS LS-6 Just my opinion
If you decide to alter the L48 just make sure you keep all the original parts
remember, you are not him, and if he wants to build up the l48, which he obviously does, it's his prerogative. not everyone wants or needs a slow corvette
Melting Slicks
Joined: Mar 2006
Posts: 3,342
Likes: 7
From: Connecticut
Originally Posted by JVM225
I am pulling the motor out in the fall. I intend to rebuild the short block anyway. I thought it was a good chance to get some better heads, cam, intake, etc..
I would like to find better flowing exhaust manifolds and run a nice true dual exhaust (2 1/2").
I know that with the GTO's that the Ram Air manifolds are much better than the stock ones, and there are companies out there that make them re-production and you can order them ceramic coated. You can also get complete 2 1/2" mandrel bent exhaust systems ready to bolt in. I was just wondering if the same exhaust options were available for the Corvettes.
I'm not a big fan of headers.
I would like to find better flowing exhaust manifolds and run a nice true dual exhaust (2 1/2").
I know that with the GTO's that the Ram Air manifolds are much better than the stock ones, and there are companies out there that make them re-production and you can order them ceramic coated. You can also get complete 2 1/2" mandrel bent exhaust systems ready to bolt in. I was just wondering if the same exhaust options were available for the Corvettes.
I'm not a big fan of headers.
Melting Slicks
Joined: Mar 2006
Posts: 3,342
Likes: 7
From: Connecticut
Originally Posted by TopGunn
Me????
ZZ4. $3788 delivered to the freight terminal down the road. The flames were extra
ZZ4. $3788 delivered to the freight terminal down the road. The flames were extra
Le Mans Master
Joined: Apr 2006
Posts: 5,403
Likes: 95
To keep it stock looking under the hood for an intake manifold do
what ajthrom did to his 69 buy an edelbrock performer and paint it
engine color edelbrocks performer will drop 20 pounds of weight off your car and they make a little more power to 5500 rpm.
for a cam cranes new Z-cam
power range 1800-5800 rpm
int. dur. .050, 218
ex. dur. .050, 230
int. dur. adv. 268
ex. dur. adv. 280
int. lift .459
ex. lift. .486
LSA 112
cam part # 113521
cam and lifters part # 113522
what ajthrom did to his 69 buy an edelbrock performer and paint it
engine color edelbrocks performer will drop 20 pounds of weight off your car and they make a little more power to 5500 rpm.
for a cam cranes new Z-cam
power range 1800-5800 rpm
int. dur. .050, 218
ex. dur. .050, 230
int. dur. adv. 268
ex. dur. adv. 280
int. lift .459
ex. lift. .486
LSA 112
cam part # 113521
cam and lifters part # 113522
Last edited by Little Mouse; Jul 22, 2006 at 09:47 PM.
Drifting
Joined: May 2005
Posts: 1,629
Likes: 4
From: Somers CT
Originally Posted by Bob Onit
Was that carb to oil pan Gunn, or did you have yo use your intake ect;?
http://www.sdpc2000.com/catalog/3508...ate-Engine.htm
