Still having problems

[Rolling_Thunder]

yes i disconnect it...    but if i hook it up to the wrong port maybe that is the problem

[Chryco Psycho]

probably

[tecmopar]

I agree with ff3931, I also never use the vacuum "retard" as I like to call it, but again if you feel you must hook it up, when looking at the ports on the front of the carb, you want to use the higher of the 2. Its only a little higher but you can see the difference, this one is above the throttle blades. Good luck.

[Rolling_Thunder]

OK - heres an update....    Engine backfires still....     Vacuum is hooked up to the correct port (I have tried both ports and disconnecting and plugging ot)  tried adjusting the mixture screws to just about every possible setting, resetted the oil pump drive gear, replaced the coil, made sure the ECU is grounded, timed to 10BTDC, made sure no spark plug wires can be the problem, and the end resut is.....        it still is backfiring.....     Any more suggestions ?   

[69chargeryeehaa]

i had simmilar problems on a 440 in my 69 charger.  start with the timing, i know you've been thru it but hear me out.  i hope you have a advanced timing light, one that you can dial in the advance.  disconect the vacuum advance and plug it, (by the way the ported vacuum port on your carb is the small one on the passenger side, looking at the engine from the front it's the left small one next to the big centre one) set your timing for 10* initial (remember vac is disconnected and plugged), then rev the engine while advancing the light to the tdc, rev until it stops advancing, note the rpm where it start's advancing, it should stop before 3000rpm.  typically, although everyone likes different advances, you should have roughly 20* advance, and it should (for good performance) all come in before 2500rpm.  then connect a vacuum guage to the non ported vac of the carb, check how much vac u have at idle, below 15 inches of vac at idle will make that carb a real pain to tune, trust me i played this game ALOT!!!  then connect the vac advance and rev the engine again and see what your total advance is, you should see about 14*deg of additional advance from the vacuum advance hooked up on the distributor.  if that all checks then focus on the carb.  if the vacuum comes in to early or late it will give you light to mid-throttle issues, at wot (wide open throttle) there is no or low vacuum where the advance does nothing.  to adjust the vacuum advance you insert a 3/32" alen key into the hole of where the vacuum hose connects to the distributor, carefull you don't damage the diaphram.  you can turn it, from memory 1 turn = roughly 2* deg.  once you have the timing all set, and your sure it's ok, your problem is in the carb, i would take it apart and check everything, making sure your jets, metering rods and springs are all stock calabration and go from there, also check the floats, and needle seats, usually back fireing is caused by flodding.  hope this helps.

[firefighter3931]

How do the plugs look....white or black or tan ? Sounds like it's running lean...you might need to jet up. Perhaps the floats are set too low ?

Ron

[tecmopar]

Just how much vacuum does it have, when you connect a vac gauge is it steady or does the needle jump around. Have you done a compression check. This is starting to sound more like an internal problem, stuck ring, bad valve, stuck valve, cam not indexed properly, etc etc, good luck.

[Rolling_Thunder]

Well I am going to take up my weekend tearing apart the carb and changing jets and metering rods       

[69chargeryeehaa]

Well I am going to take up my weekend tearing apart the carb and changing jets and metering rods       

check out this edelbrock manual, i found it really helpfull for understanding what does what, and the charts for jetting:
http://www.edelbrock.com/automotive/eps_intro.html#contents

also you might want to give edelbrock tech dept a call, i found them really helpful:
If you need to speak with an Edelbrock technician by phone, please call 1-800-416-8628 from 7:00am to 5:00pm, Monday-Friday, PST.

don't worry it's free!!! and these guys really know what they're talking about, they even sent me jets, metering rods and springs for free, just sound like a unhappy customer, but concerned with the carb and they will go out of their way to help you if your polite.

[BrianShaughnessy]

   Did anybody bother to check the fuel pressure on this?   Could be one of them super duper carter race pumps that spits out about 9 or 10psi to the carb.   Usually way too rich and the plugs get all fouled out in a hurry. 

[Rolling_Thunder]

well I have the car running alot better now...   now my only problem is slight stumble when i put my foot to the floor...   but It runs...     I set back the initial timing, richened up the mis some, and adjusted the mechanical advance in the distributor...    runs better except like i said - stumble on HARD acceleration....    I think the secondaries might still be leaning out at higher RPM's

[68 RT]

My car did this to with a 750 edelbrock. Changed step up piston springs. Cured the problem. But still ran lean. Ended up changing rods and jets up one step. Buy a tuning kit for your edelbrock. I believe this will solve your stumble.

[69chargeryeehaa]

My car did this to with a 750 edelbrock. Changed step up piston springs. Cured the problem. But still ran lean. Ended up changing rods and jets up one step. Buy a tuning kit for your edelbrock. I believe this will solve your stumble.

i agree