q-jet CFM
Thread Starter
Heel & Toe
Joined: May 2003
Posts: 21
Likes: 0
From: Allentown Pa
q-jet CFM
I have a rochester off a '79 auto corvette on my '84 corvette.
not happy with the carbs performance and am trying to find the cfm's on the stock '79 vette carb so I can get an equal holley.
any help
Harry
not happy with the carbs performance and am trying to find the cfm's on the stock '79 vette carb so I can get an equal holley.
any help
Harry
Race Director
Joined: Aug 2004
Posts: 10,628
Likes: 132
From: Duvall, WA
The stock Q Jet is 750 cfm, which translates to a 600 cfm Holley. Your '84 should be fuel injected, of course. Rather than switch to a Holley, I would tune the Q Jet properly, or have it done if you aren't up to the task.
Intermediate
Joined: May 2006
Posts: 33
Likes: 0
From: Palm Beach Gardens Florida
Originally Posted by rcread
The stock Q Jet is 750 cfm, which translates to a 600 cfm Holley. Your '84 should be fuel injected, of course. Rather than switch to a Holley, I would tune the Q Jet properly, or have it done if you aren't up to the task.
Le Mans Master
Joined: May 2006
Posts: 9,993
Likes: 1,136
From: League City Tx
Originally Posted by torqvette
Why in the world did you give up FI for a Q-Jet? I could see putting a carb on a C4 if you were dropping in a potent stroker but then you wouldn't be using a Q-Jet. 
Because 84 had the crap-fire injection... 85 was TPI. I would rather have a ratty *** q-junk then the crap-fire.
Le Mans Master
Joined: Apr 2006
Posts: 5,403
Likes: 95
Can I make a suggestion if you are going to spend the money for a new
holley or demon, buy one that has anular boosters unless you are an all out RPM drag racer. Vacuum secondaries make sense for a street car,
every hi po engine chevy built with a holley had vacuum secondaries.
( yes the race motor L88 had a double pumper ) If you are going to have your car on the drag strip all the time get a double pumper.
( they drink a little more fuel and have more parts to screw up )
Demon has carbs in 750 to 850 cfm, anular boosters with vacuum secondaries or double pumper. Holley may have the same thing.
holley or demon, buy one that has anular boosters unless you are an all out RPM drag racer. Vacuum secondaries make sense for a street car,
every hi po engine chevy built with a holley had vacuum secondaries.
( yes the race motor L88 had a double pumper ) If you are going to have your car on the drag strip all the time get a double pumper.
( they drink a little more fuel and have more parts to screw up )
Demon has carbs in 750 to 850 cfm, anular boosters with vacuum secondaries or double pumper. Holley may have the same thing.
Last edited by Little Mouse; Jun 12, 2006 at 09:49 PM.
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Instructor
Joined: Apr 2006
Posts: 174
Likes: 0
From: Wallaceburg Ontario
Originally Posted by Little Mouse
Vacuum secondaries make sense for a street car,
every hi po engine chevy built with a holley had vacuum secondaries.
( yes the race motor L88 had a double pumper ) If you are going to have your car on the drag strip all the time get a double pumper.
( they drink a little more fuel and have more parts to screw up )
every hi po engine chevy built with a holley had vacuum secondaries.
( yes the race motor L88 had a double pumper ) If you are going to have your car on the drag strip all the time get a double pumper.
( they drink a little more fuel and have more parts to screw up )
I wish I had a dime for every time I've run into someone who thinks they've GOT to have a double pumper regardless of whether or not the car will ever see the 1/4 mile. Even though I'll hit the track a few times each year, I'm goin' with the vac. sec. Fewer headaches.
Le Mans Master
Joined: Jun 2002
Posts: 8,339
Likes: 24
From: I can walk to MA
Originally Posted by Kalway
My advice:
Fix the q-jet. A holley isn't going to solve your problems.
By the way, how's your timing? Like Lars says, that's what the majority of problems people attribute to carbs are.
Fix the q-jet. A holley isn't going to solve your problems.
By the way, how's your timing? Like Lars says, that's what the majority of problems people attribute to carbs are.
