426 Hemi trouble??

[B5BEE]

So me and my brother dropped a 426 Hemi in his 72 satellite this week and weve been having a fuel issue. the carbs are 625cfm carters its a dual quad setup with the spread bore aluminum intake. engine mods are stock heads mopar steel crank, eagle rods, trw pistons, stock cam with altered duration, 11:1 compression,running 93 octane,727 trans with 9" 5k stall converter. stock ignition, and timings at 38degrees.
The engine will idle in neutral at about 13-1400 rpm, once I drop it into gear it goes to 900rpm and I have to 2 foot it to keep it going, not a big deal but she will stall out if I dont 2 foot it or throw it in neutral before stopping. Also when taking a turn she conks right out. Im running a holley blue pump 1/2" line and pressure is at about 5.5psi.
So ive changed the carbs to a set of 1405 edelbrocks that were on my fathers hemi which we know run fine and im still experiencing the same problem. I now have the valve covers off and Im gonna check valve lash once my father gets home. Spark Plugs are gapped at .032,

Could the converter be too loose with the cam and making it load up?
Float levels? Although they should be fine because they ran on the other motor.
Ignition system? What could it be?

Also this is a second hand motor I know where it came from and who built it. It was a stock eliminator motor built for a 69 roadrunner, I need to find out the cam specs.

 

[HitIt]

It sounds like symptoms of a classic vacuum leak. did you check that out?

It could be float levels but my edelbrock had them all screwy before I set them and it never died when coming to a stop. Did you set your idle circuit mixture screws?

 

[B5BEE]

It sounds like symptoms of a classic vacuum leak. did you check that out?

It could be float levels but my edelbrock had them all screwy before I set them and it never died when coming to a stop. Did you set your idle circuit mixture screws?

Going to try the Idle circuit screws tomorrow, and the vacuum's are all plugged but they were dry rotted so I just switched them out with new ones. Gonna start it tomorrow and see what we got. Thanks.

 

[66blvee]

Make sure both carbs are at the same spot on the curb idle screw. In the motorcycle world we call it syncing the carbs.

 

[Meep-Meep]

Thinking out loud about your problem and the info you gave about your engine here are a few things that come to mind:

If you are loading up then that is a fuel issue and you should check if the floats are actually shutting off the fuel. Maybe a piece of crud got in from your fuel system? Also what is your vacuum at idle in gear? If it is something like 5 in-Hg then chances are your power piston springs are too stiff and holding the metering rods in the full power position. To verify this swing the covers from the power pistons off to the side just enough to see the piston under it but not all the way off so the pistons pop out. Start the engine and you should see the pistons get sucked down to the bottom. If not then you need lighter springs. The carb maker has all the info on how to select the proper spring.

Another radical cam idle fix is to to drill a small hole (about .040") in the throttle blades NOT near the transfer slot. This will allow more air to enter the engine at idle without having the throttle blades open so far that they drain the transfer slot. This is a last resort AFTER you have checked that everything else is working properly. Are you running them progressive? If so then the rear carb will do most of the idling and the front carb can have the throttle nearly shut off. Otherwise set both carbs the same and in all cases have the linkage pick up the shafts evenly.

I doubt a loose converter has anything to do with the near stalling - unless it's messed up somehow and trying to lock up.

You might also look at the ignition system. A weak ignition will have even a harder time firing a lean mixture because a radical cam will mess with the fuel mixture and distribution at low speeds and a lean mixture is hard to ignite. By the way as I understand it there are only two advance settings for a HEMI. 32 and 62, with the 62 being for fuel. I don't think six more deg of total advance is having an effect on your problem though.

 

[SUPERSTOCKRACER]

AIR MIXTURE SCREWS.turn them all the way in and out 2.5 turns. staert the car and in idle turn each one out till idle is at maximum, 1 by 1 .
your probably too rich at idle.