WE HAVE BOTTOM!!!

[challenger72rt]

ok, now that the starting problem was solved by disconnecting the faulty Tach, she fires right up, and runs reliably.  Here's the problem.  The motor (440) was built totally for bottom end, and was mated to 3.91's to plant the 15's firmly.  Before I swapped the intake, and rebuilt the carb, she'd lay 40 feet off the line without even trying, and I have DOZENS of kill stories from a stand still.  Now, the mid-to-high range is ok, but she's LOUSY off the line!!  Altho she has high comp., I am using Av Gas with 100 octane, so it's not that.  I gun it off the line, and I get no chirp, not even a bark...just walks off the line, and gradually ponies up.  If I rev high, it'll bark from 1st to 2nd (slap-stik) but that's it. 

I am planning on attending an all-Mopar day at the local drag strip next Sat., and don't want my 500+HP 3,300Lbs. Chally EMBARRASED! 

Now then...before the carb was rebuilt/installed, I didn't attach the vaccuum line from the distributer to the carb, and it didn't have a choke plate, but now it has a choke plate, and the vaccuum line is reattached.

I'm not convinced that I have tuned the carb to its optimum performance, either.  I have played with the idle, and mixture, but is there anything else to adjust?  It's a Holley 750, vaccuum 2ndaries.

The other thing is, could it be that my fuel pump isn't cutting it anymore?  It was fine before, and ran healthy as all get-out, so I doubt adding a performance intake would be SO drastic that the pump can't feed it enuff anymore...right??

thoughts??  What would rob a car of low-end power SO badly?

Please help!

[Bullitt-]

timing ?

[challenger72rt]

timing was set last year, and just changing an intake shouldn't affect it...I don't think.

[Bullitt-]

I'm no expert but my take on it is that is all relative. One modification changes everything. What your engine needs was altered by the difference in intakes.

[Killer_Mopar]

timing ?

Im going to say timing too. Is the distributer a vacuum advance or mechanical? if its a vacuum advance then changes in the vacuum line could certainly throw everything off.....

[ShelbyDogg]

I bet if you showed us both of your intakes, we can help you.
Rob

[challenger72rt]

well, if it helps, the old one was the stock cast iron 4Bbl 440 intake, and the new one is an MP performance dual plane aluminum jobbie.

I'll see about pics this weekend if it'll help.  Should I take any of the dist., too?

[Bullitt-]

A good vacume leak could cause also. have you had any problems getting it to idle down or after you rev. it in neutral does it take a long time to come back to idle?

[4drbrnko]

Didn't you have to pull the dizzy to swap intakes?
I'm betting on timeing.

[Chryco Psycho]

intake definatly can kill bottom end power & the addition of he vacuum advance hoise probably has the timing all screwed up too . most car run better withj more intial advance & no vacuum advance

[ShelbyDogg]

When you rebuilt the carb, did you change power valves? (I don't unless they're bad or I'm tuning)
Did you use a holley clone-kit or jut change gaskets.  Put a paper clip on your vacuum secondary diaphram shaft up against the vacuum pod to see if it moves down the shaft and how much travel it moved. I usually don't pull my distro to change the intake.

I agree 3:91s and 500 HP would smoke my tires till the money ran out for new ones.

[challenger72rt]

A good vacume leak could cause also. have you had any problems getting it to idle down or after you rev. it in neutral does it take a long time to come back to idle?

Kind of the opposite.  Sometimes I start it, and idle is really high, then I blip the throttle, and it calms down to 'normal'.

[Killer_Mopar]

Kind of the opposite.  Sometimes I start it, and idle is really high, then I blip the throttle, and it calms down to 'normal'.

That sounds like the choke is sticking, try jamming the choke open and go for a drive to see if it still does that.

[challenger72rt]

well, my intention is to completely remove the choke plate, and the vaccuum line from the dist. to the carb, and see what happens,since that's exactly how it was when it actually worked!  gunna look into the timing, too.

Unfortunately, it won't be til Friday when I get to it, and the races are Saturday.  Looks like a late night of knuckle bustin'!!  Ah, Yeah!! 

[MEK-Dangerfield]

well, my intention is to completely remove the choke plate, and the vaccuum line from the dist. to the carb, and see what happens,since that's exactly how it was when it actually worked!  gunna look into the timing, too.

Unfortunately, it won't be til Friday when I get to it, and the races are Saturday.  Looks like a late night of knuckle bustin'!!  Ah, Yeah!! 

      

  Sounds like a good plan to me!!  Just be sure to plug the hole going from the distributor into your carb. You don't want the carb. sucking in unmetered air. Also, the timing should be easy to set with the fuel you are running. Just use Chryco's "listening" method. Loosen the clamp holding the distributor in place. Start the car... then slowly turn the distributor left and right, to find it's happy zone. That's where the idle is running best. I know he recommends revving to 3000 RPM, so you are setting it at total advance, but my ears can't take that.     

  Mike