Carb Question - 1972 LT-1
Thread Starter
Instructor
Joined: Aug 2004
Posts: 244
Likes: 2
From: Miramar FL
Carb Question - 1972 LT-1
Hey guys - quick question on opinions. My 72 LT-1 (4-speed no a/c)runs with some strange idle (I read anearlier thread on a similar problem someone else had with inconsistent idle speeds). My mechanic suggested moving to a Rochester q-jet carb and getting rid of the Holly Street Avenger that's currently on it. He's had better results and performance with q-jets over the Holley's - he wasn't pushing it though, just throwing it out as a possible option.
1. The LT-1's came with Holley's (at least according to the black book and other articles). Is it a big deal from an originality perspective - i.e. would I severely mess up my value/future appreciation?
2. Would this really help out my performance/ has anyone else with an LT-1 done this?
Thanks!
1. The LT-1's came with Holley's (at least according to the black book and other articles). Is it a big deal from an originality perspective - i.e. would I severely mess up my value/future appreciation?
2. Would this really help out my performance/ has anyone else with an LT-1 done this?
Thanks!
Drifting
Joined: Sep 2004
Posts: 1,959
Likes: 1
From: North Bend Ohio
Describe the problem. Maybe it just needs to be cleaned and rebuilt. The Q-jet is a good carburetor but no sense in spending all that money if a $40 rebuild kit will do the trick.
BigBlockk
Later.....
BigBlockk
Later.....
Race Director
Joined: Dec 1999
Posts: 19,610
Likes: 778
From: Forked River NJ
The Q Jet will not fit on the intake. It is not a square bore carb. If you are going to replace the carb get the right 780 vacuum or a 750DP. You should be able to get the Avenger to work with a rebuild and adjustments.
Thread Starter
Instructor
Joined: Aug 2004
Posts: 244
Likes: 2
From: Miramar FL
Thanks for the input guys. As for the problem, basically, she sometimes will idle up at 14-15 (no set pattern to it), while she normally idles at 5-6. My mechanic turned the adjustment screw yesterday to set the idle a little higher at 8 to at least take care of the bottom end since I didn't like it as low as it was. To my knowledge, the carb is clean and like new. When I bought her, the previous owner had done a lot of restoration and mechanical work (engine bay was immaculate) and nothing like this came up during the test drives and inspection. Last night during a short drive, I hit stop and go traffic for the first time and she proceeded to stop on me everytime I was coasting to a stop. She started back up each time, but then would stop again after coming out of first or second and into neutral. Once traffic started moving again, all was well.
Le Mans Master
Joined: Dec 2003
Posts: 5,727
Likes: 38
From: Fremont CA
If you have to use a mechanic to adjust your idle, you should really consider selling your LT-1. LT-1s tend to be "high maintenance" but, return VERY HIGH PERFORMANCE for their demands. It sounds like the carb float levels or float my be sticking. You need to purchase a shop manual and learn to troubleshoot for your self. There are plenty of people here with years of knowledge that are willing to help.
Thread Starter
Instructor
Joined: Aug 2004
Posts: 244
Likes: 2
From: Miramar FL
Originally Posted by Solid LT1
If you have to use a mechanic to adjust your idle, you should really consider selling your LT-1. LT-1s tend to be "high maintenance" but, return VERY HIGH PERFORMANCE for their demands. It sounds like the carb float levels or float my be sticking. You need to purchase a shop manual and learn to troubleshoot for your self. There are plenty of people here with years of knowledge that are willing to help.
Burning Brakes
Joined: Feb 2005
Posts: 977
Likes: 1
From: wash. dc
carb questiion
the first book i got after purchasing my 71 ls5 was a hanyes repair manual...later got the assembly instruction manual and a shop manual...these three usually solve any problem i have along with the expertise of these generous members here on this forum
