Hello everybody looking for a little help I have had my 406 into the car now for a week "85 z28" and I'm really pleased with it except for one problem I have a hesitation from 2000-3000 under load more noticeable in 3rd gear under load less in second gear it's a 700r4 a 750 cfm edelbrock shorty headers and a custom 3 inch I fabbed up myself. I have changed the cap, rotor, plugs, and wires thinking about trying the ign module and switching back to the 600 cfm eddy off my 305 any suggestions would be great.

 

 

Is that first pic the Y pipe?

My friends 350 had a similar design and an odd stumble when we got on it. Spent days working on carb tuning and ignition and in the end when we put a proper Y pipe and merger on it the stumble disappeared.

 

That's interesting if that's the case, the stock y was much the same tho it was like 2 inch into 2.5

 

There are other causes, I would try adjusting the accelerator pump and get a spring tuning kit but

Not saying it is 100% the same but when from this



To this it was amazing and 100% unexpected.

 

I was thinking the accelerator pump actually... It is set up for the largest squirt... Gigidy. Which may be to much for this setup

 

Try changing it around and use a vac gauge to check the springs.

 

Moved the accelerator pump to the middle position hesitation all but gone now gonna move it down one more step and try it.