[C2] 427/425 Holley 4150 Fast Idle adjust
10-21-2016, 10:57 AM
#1
Drifting
Thread Starter
Member Since: Jun 2000
Location: Southern NJ
Posts: 1,596
Received 52 Likes
on
33 Posts
C2 of Year Finalist (stock) 2019
427/425 Holley 4150 Fast Idle adjust
I am trying to do a final fast idle adjust on my Holley 3247 (4150). I have read John Z's article and the Chev Chassis Overhaul Manual on how to do this however I still have a question. I know I have to bend the tab that controls the step on the plastic cam. The question is -- when and how do you bend it. I know you use a flat bladed screwdriver. Do you bend it with the plastic cam all the way down and out of the way ??? Do you bend it with the plastic cam half way up ?? How firm should the tab be against the plastic cam ?? thanks in advance
10-21-2016, 11:11 AM
#2
The Holley fast idle adjustment is done with a warm (hot) motor. After a drive, remove the air cleaner and place the plastic cam on it's highest step and bend the tab (which will open the throttle blade) so when it sits on the highest cam step the engine rpm is at the book spec.
Example, my 67 300hp engine is 2000rpm, don't worry about the other cam steps, just the highest step.
Example, my 67 300hp engine is 2000rpm, don't worry about the other cam steps, just the highest step.
Last edited by tbarb; 10-21-2016 at 11:13 AM.
The following users liked this post:
JL66REDCPE (10-22-2016)
10-21-2016, 12:19 PM
#3
Drifting
Thread Starter
Member Since: Jun 2000
Location: Southern NJ
Posts: 1,596
Received 52 Likes
on
33 Posts
C2 of Year Finalist (stock) 2019
I'm sorry - I still dont understand. Bending the tab does not open the throttle blade. I am surprised that you do this to a warm engine. I need more detailed info on how to do this.