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Intermediate
Joined: Feb 2008
Posts: 39
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From: Foley Alabama
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Just found the site and looks like a great site!!
I am starting to "refresh" my dads 1977 vette for him that he bought brand new back in '77. Outside of what has been repaired/replaced under routine maintenance, the car is 100% original and only has about 80k original miles. The car looks great, but at the original 180 hp (L48 MT) it is a little slower off the line than I want it!!
I have researched the web for performance info on how what upgrades will generate what result, but information seems limited at best. I have a little gas engine experience, but have extension diesel engine experience and am a very capable mechanic in building an engine to a spec. Surprisingly cars have just never been a hobby of mine.....until now!
I am not looking to build a race car and not interested in a crate engine. I want to be able to return the car to "numbers matching" status if I so desire one day and don't want to store a complete engine somewhere.
First thing I am thinking about doing is the exhaust. I want chrome tips coming out the back, and want a sweeter sound than the stock exhaust system has. Anyone have any idea how much hp improvement I can get by going with true duals over the stock exhaust?
Anyone know what CFM the stock quadrajet is set for out of the factory? I am pretty sure the carb needs rebuilding as it is all original and 31 years old (I have changed the filter in it) - can anyone recommend a good place for this? I have thought about just buying a new carb (holley or edelbrock) and a new intake manifold and just storing the old, but I have read that that model quadrajet can be adjusted to 850 cfm so I'm not sure I need a complete new carb.
Without changing heads and adding a cam, anyone got any idea what hp limitation I have?
Thanks in advance for any information
I am starting to "refresh" my dads 1977 vette for him that he bought brand new back in '77. Outside of what has been repaired/replaced under routine maintenance, the car is 100% original and only has about 80k original miles. The car looks great, but at the original 180 hp (L48 MT) it is a little slower off the line than I want it!!
I have researched the web for performance info on how what upgrades will generate what result, but information seems limited at best. I have a little gas engine experience, but have extension diesel engine experience and am a very capable mechanic in building an engine to a spec. Surprisingly cars have just never been a hobby of mine.....until now!
I am not looking to build a race car and not interested in a crate engine. I want to be able to return the car to "numbers matching" status if I so desire one day and don't want to store a complete engine somewhere.
First thing I am thinking about doing is the exhaust. I want chrome tips coming out the back, and want a sweeter sound than the stock exhaust system has. Anyone have any idea how much hp improvement I can get by going with true duals over the stock exhaust?
Anyone know what CFM the stock quadrajet is set for out of the factory? I am pretty sure the carb needs rebuilding as it is all original and 31 years old (I have changed the filter in it) - can anyone recommend a good place for this? I have thought about just buying a new carb (holley or edelbrock) and a new intake manifold and just storing the old, but I have read that that model quadrajet can be adjusted to 850 cfm so I'm not sure I need a complete new carb.
Without changing heads and adding a cam, anyone got any idea what hp limitation I have?
Thanks in advance for any information
Le Mans Master
Joined: Apr 2005
Posts: 6,357
Likes: 427
From: Seattle Area WA
Welcome aboard.
Contact Lars for your Q-jet and distributor rebuild, V8fastcars@msn.com
As for your carb, it should be 750 cfm Q-jet. As for getting rid of the "Cat" and adding true duals, it will helps some but don't expect any miracles out of a stock L-48 with 8.2:1 compression. You'll more than likely want to add heads with smaller combustion chambers, a Performer intake and a little bigger cam to get any power out of it. The forum is full of guys who have done this basic swap. The Vortec heads and short duration cam like a Summit K1103 seems to be a good basic combo.
Contact Lars for your Q-jet and distributor rebuild, V8fastcars@msn.com
As for your carb, it should be 750 cfm Q-jet. As for getting rid of the "Cat" and adding true duals, it will helps some but don't expect any miracles out of a stock L-48 with 8.2:1 compression. You'll more than likely want to add heads with smaller combustion chambers, a Performer intake and a little bigger cam to get any power out of it. The forum is full of guys who have done this basic swap. The Vortec heads and short duration cam like a Summit K1103 seems to be a good basic combo.
