Ok, im at my wits end on this one.
Here is the run down:
Brand new Quick Fuel Slayer 750 vacuum.
Current setup, 70 jets, 3.5 power valve, idle air screws only 1/4 turn out.
Hammer down from rolling 25 up MPH, falls on its face and shutters.
Put in neutral and it revs fast to the moon?
There is (rough) miss at a certain point, same spot with or without vacuum hooked to constant vacuum source once I adjust idle back to 1000rpm idle in park.
I had a problem earlier and did blow the power valve because its not as rich with the new power valve.
My idle vacuum is 14 in neutral I don't know what it is in gear?
Anyway:
Should I just go back to the 72 jets, change power valve back to a 6.5?
But not saying that will help anything but start at a base setting.
Idle air screws go out any at all and it losses vacuum and run rough.
If you want to help just ask a question, I know its alot to dig thru but any thoughts???

 

A 3.5 is to small if your carrying 14 In of vacuum you need that 6.5. Doesnt that slayer have changeable air bleeds? If it does sounds like it may have to small of air bleeds in the idle circuit making run rich. Just a guess.

 

Yea Im sure I will change back to a 6.5.
What about the jets, stay with the 70s or go back to the 72s that came in it?
Where in the world do ya get the changeable air bleeds at???

 

Better find out what it has for vacuum at idle in gear. Most street carbs will need the 6.5 PV. Go back to square one and start all over IMHO.

 

Even when I start over I know the air idle screws will only go out 1/4 of a turn before it starts running rough and losing vacuum on a gauge.
Im going to do some research and see what im going to do.


***Here is a kicker for ya! Brand new plugs are snow white!

 

Your making the mistake of associating jet size with the idle circuit. If you have a lopey cam, set your idle mixtures screws where it idles best, not by highest vacuum. Put the 6.5 power valve back in there adjust your idle speed down to 750-800 rpm. For grins and giggles use ported vacuum for your vacuum advance. See how it idles there.

 

x2

 

The needle and seat was sticking closed, little orange rubber valve thingy was broke in the 30cc pump, no gasket on the screw or adjusting nut.
I put the 72 jets and 6.5 power valve back in and the car lopes again, idles at 700RPMs in gear and no more stumble or anything negative!
I think it could handle bigger jets but im done, I got hours of cruising to do in 3 weeks!