new carb hesitating a bit

[v8s10kid]

i just put a new holley 570 cfm street avenger on my s10. it seams to hesitate till about 2700 2800 rpms then takes off. are the secondarys opening too late?

a little info:
1984 chevy s10
305 small block
edelbrock performer intake
shorty headers
2.5 inch custom exhaust with flowmaster mufflers
pertronics electronic egnition conversion
muncie m20
3.08 rear
weights about 3240 with me in it (thank you scrap yard)

altho my old edelbrock carb ran a little rough, it never hesitated like this. also, i didnt change anything else. timing is still the same, and i havnt put new plugs in yet. the vacume advance line should go to the port on the side of the metering block right? or to the port at the base plate?

[v8s10kid]

new msd wires, put in the lighter long yellow spring. still hesitates.

fouled plug?

come on guys this is my daily driver, i need to get it running good yesterday.

[ivmotor]

Did you check float levels yet? Do you have any way of knowing rich or lean? How much vacuum does it pull at idle? You should set your power valve just below that number so it opens under acceleration. You could install bigger jets and try the drive again and see if it improves. Your accelerator pump circuit could be plugged, or the wrong cam/nozzle combo. Watch the nozzles and crank the throttle, you should see a pretty healthy "squirt". Do you have a timing light to verify the timing hasn't changed?

[Vegas69]

Is this during normal driving or full throttle?

[GregWeld]

I just put a brand new out of the box Holley 650 on my buddies '32 Ford... got it running fine but not "perfect". I thought it was pig fat cause it felt a bit lazy in the bottom end... and it had a bog if you jumped in it.

Bottom line was -- we took it to the dyno -- it wasn't pig fat -- it was LEAN -- and needed the squirters resized (drilled out) and two jet sizes bigger in the primaries...

Here's what I'm trying to say:

Some of this stuff takes a pro and takes equipment (tail pipe sniffer etc) to sort out even if you're real familiar with carbs and timing etc. You could spend days trying to sort out all the advice and tips you're going to get in forums like this.

[v8s10kid]

i have no way of telling if its rich or lean. i dont have a timing light or a vacume gauge.

it does it in both normal and full throttle driving.

i got new plugs ill change em tomorrow and check a few more things but if i cant find it one of my dads friends builds and races modifieds at the local circle track, hopefully he can sort it out.

normal driving it has a lack of power and seams to bog a bit. full throttle it hesitates till about a quarter up the rpm band then it suddenly has this massive release of power. when i let off the gas it does pop and sometimes backfires.

[Ron in SoCal]

Originally Posted by GregWeld

Here's what I'm trying to say:

Some of this stuff takes a pro and takes equipment (tail pipe sniffer etc) to sort out even if you're real familiar with carbs and timing etc. You could spend days trying to sort out all the advice and tips you're going to get in forums like this.

What Greg said. I had a new Holley 750 do the same thing you're describing. I spent hours trying to get it right, with help from so called 'carb tuner' friends. Took it to a tuner, ran great right after that. Good luck...