need help, when i step on the gas it dies

[MikeMacCham]

hey guys,
I have a 68 charger with a after market 440, bored 40 over. We just put a 770 dual pumper Holley carb on it that came with larger fuel lines, i think like 71 or something. Before this carb it was firing through the exhaust. the timing it advanced i think like 12,  and then at high rpms it reads like 40 or so. the car just barely fires through the carb at full rpms at higher speeds. but what I would REALLY like to fix it the problem of NOT being able to peal out at every stop sign. If I floor it from 0 miles per hour it is like flipping off a light switch, the engine stops, if i let off the gas it will start immediately it won't die but if i keep it floored it dies. If I power break it it will peal out. it seems like it should be a fast off the line set up. What could be wrong?

[70charger_boy]

I'm not an expert, but did you check your vacuum lines to make sure they are connected and no cracks?  Also try disconnecting and plug the vacuum advance line and see if that helps

[Steve P.]

40* of total timing is too much. Should be in the 34* range full in.

[firefighter3931]

Sounds like a timing issue to me. If you set the base timing with the vac advance hooked up it will actually pull timing out of the motor when you floor it off idle. I allways disable the vac advance and tune w/o it.

Assuming that timing is not the issue i would start looking at the fuel delivery. It could be going lean momentarily due to accelerator pump adjustment or incorrect power valve selection.



Ron

[MikeMacCham]

thaanks guys, i'll check on that stuff today! I have been out of town.

[chargerman68]

40* of total timing is too much. Should be in the 34* range full in.

retard it some see what happens

[jg68]

This is just my opinion , 40* total timing shouldn't cause it to stall out, it may ping or miss, but i think the stalling is do to not enough fuel somewhere, i would check the fuel levels at the sight plugs, make sure there right at the edge (just sweating out at idle) & get the highest (& steadiest) vacuum reading on the mix screws, also check for vacuum leaks, if all this checks out & or it still does it, make sure your getting a nice steady stream of fuel out of the squirter.

But i will agree 40* is too much total timing, 36* total is about as much as i would run on pump gas

[John_Kunkel]

If I floor it from 0 miles per hour it is like flipping off a light switch, the engine stops, if i let off the gas it will start immediately it won't die but if i keep it floored it dies.

The carb is too big and needs to be jetted richer to compensate for the excessive airflow.

[TylerCharger69]

I had the same problem here recently and come to find out, my fuel pump was taking a crap.  It started to do it all of a sudden.   It would idle fine, but once I stepped on the gas...it would die.  The fuel pump had just gotten weaker.  I replaced it...problem solved.   BUT...I'm not saying that's your issue.....but it's another possibility.   It's also possible that you are dumping too much fuel as well thus causing it to flood out when you accelerate.  Check the spark plugs and see what they tell you.  They tell a great story if you know what to look for.  Just my   

[Chryco Psycho]

If I floor it from 0 miles per hour it is like flipping off a light switch, the engine stops, if i let off the gas it will start immediately it won't die but if i keep it floored it dies.

The carb is too big and needs to be jetted richer to compensate for the excessive airflow.

Say What 770 cfm on a 440 is too big 

tuning seems to work well

[MikeMacCham]

Sorry guys, its been a busy week. And on top of that I am like half way done with changing my interior color. Lets see...I will see what happens when we retard the timing down a little, no the vac was not attached when I checked the timing. I was wondering if maybe somthing is stuck in the fuel line, the car didn't have a fuel filter on it until a week ago. I will check the stuff you guys mentioned tommorow and let you know, thanks a ton guys.