Bought a 4160 600CFM for my 1969 Cutlass w/ 350 (rebuilt mild performance style). So I'm getting some hesitation/bog off idle. My vacuum is around 11 at idle in gear on my auto.


Read up on tuning, and apparently there are about 15 different components to tune on this thing (jets, idle mixture, squirter, cam, acc. pump, power valve, ...). Did I make a mistake?


Guess my issue is, apparently everything I read says to try out different components to see what performs best. So apparently I have to buy $150 worth of parts to just see if I can get it tuned. Then I guess toss the rest?


Any help/advice would be appreciated.

 

You're going to need someone knowledgeable on Holleys to be there. Trying to get it straight over a forum could take days.

 

Did you get your timing dialed in?
https://classicoldsmobile.com/forums...9-cutlass.html

 

This would be my first step

 

Sure did, thank you. Put on one light silver spring and timed at about 16-18 at idle as you suggested. My timing marks only go to around 14, so kinda eyeballed it. Thing screams on the highway.


Do you feel this could still need some adjustment? This wouldn't cause hesitation, right?

 

And TripDeuces, I saw that video. You're right, I do need to try that first.

 

Did you change the stop bushing? At what rpm did you set the timing? I'm also concerned because your vacuum is at 11. Do you have any leaks, all vacuum tubes connected or capped?

 

As best I know, no vacuum leaks. Have not tried the bushing yet, it ran pretty nice after just setting the timing and changing the spring, so didn't want to further disturb it.


Not sure on RPMS, don't have a tach. Guessing the 16-18 was around 1200-1500.

 

Not trying to be an a$$, so don't take this the wrong way. You've invested a lot of money in components for your engine. Until you get the proper tools and do the timing and setup correctly, you may be creating other issues. As you fix these issues that you create (some of which can cause real damage), the engine setup gets farther and farther from running correctly. You might as well have just stuck with what came on the car from the factory.

 

Understood. I've kind of exhausted my car funds for now, so thinking I will just run it as is until I can drop a little more cash into it.


I appreciate your efforts.