Need Tuning Help - Philadelphia Area

[am3rican]

I'll start off by saying I have never worked or owned a carburated engine in my life, except a chain saw. I picked the mother of all cars (a 440 6 barrel) and am way over my head with it. I just don't feel comfortable with it at all.

Does anyone know someone in the Philadelphia area that knows how to tune a 6-pack? I've called A LOT of places and no one knows how to tune it. The only place I could find who said they experience said that it would take about 16 hours (at $95), so I know they were full of it.

I recently replaced the leaky throttle body gaskets and don't feel like it is running right. It stumbles at idle. Not too bad. I adjusted the idle, but without a tach, it's hard for me to tell. It has a moderately aggressive cam. There does not appear to be a vacuum leak. I did the carb cleaner test in all the obvious places. My vacuum is at 12 in/hg.

 

[HawkRod]

Try Montgomery's Automotive in Jenkintown. This is Ken Montgomery's shop, the legendary '555' drag racer. I think his son now runs the shop, and they are big Mopar guys, albeit usually with Hemi's. It's been awhile since I have been down there, but they may be able to help you out. Try 215 576 9305.

 

[am3rican]

ha...I live in Abington. thanks so much for the recommendation. I heard Ken Montgomery passed away, so I thought the shop closed. Ill give them a call

 

[am3rican]

I called Ken, he said he's busy for the month and probably couldn't look at it until early September.

Sent from my SAMSUNG-SM-N910A using Tapatalk

 

[RJRENTON]

I own a 6 barrel car. There is no great mystery about tuning the car. You should have a tach or use the dash tach if it works. It depends on the year or if the carbs are original. I believe in '71 the center Holley used a "backwards" idle system, meaning the system used a fixed fuel restriction and the mixture screws are variable air bleeds. Screwing the adjustment needles in or clockwise richens the mixture by reducing the air. If the center carb is pre '71, the idle circuit operates normally, counterclockwise rotation increases the fuel feed; the air volume is fixed thru the outside air metering restrictions seen looking down the air horn.
The end carbs have both fixed air bleeds and adjustable fuel needles, visable by looking at the throttle body, behind sealed plugs, that are removable whrn the carbs are removed from the engine. Usually, a 1/4 turn CCW will richen the mixture enough to eliminate the stumbling you note. If the distributor has a hot idle retard feature thru the vacuum advance and a connection thru the hot idle adjustment, this mechanism will also cause an off idle stumble. You do not say what specifics about your car.
Perhaps prior owners have adjusted or modified everything on advice of "carb experts" who have no real clue how a carb operates. There is a person on Ebay selling a kit to be able to adjust the back end carb (and front carb also) with the engine running. He is using a ball end hex wrench and his own designed mixture screws with a socket head hex to accept the ball end hex wrench....real slick....reasonably priced.
The real method of determining mixture setting is read the spark plugs....they will tell the mixture distribution and how the engine is running. BTW....I use Champion UJ-11G plugs gapped at 0.032". I also use a Prestolite dual point distributor with a total of 35 degrees all in by 2200 RPM no vacuum advance. Spark plug selection, advance settings and carb mixtures must be with the car owner. Comments.....questions....?
Cheers,
RJRENTON

 

[old timer]

Good idea to pick up ' The Mopar Six Pack Engine Handbook ' . Lot of info and improvements . The six pack is a thing of beauty...if it's running/set up right . Dedicate yourself to it or do yourself the favor and go with a single plane/double pumper combo as it will be a lot easier to keep in tune . Good luck...

 

[snakeoil24]

Ame3rican first thing is check the throttle body shaft to see if it is loose or too much play in the body "Center carb". Then next thing is open hood and while car is running mist the spark plug wires with water and see if they arc, since your motor has a bit of a cam your going to need a rpm meter to check for vacuum leaks. With rpm meter hooked up spray around hoses and wiggle them.. watch meter. cams that are radical reduce signal to carbs at low rpm. Also look in center carb and make sure throttle plates are covering the the slit on the idle circuit..

 

[zupanj]

I like JD Auto Repair in Huntingdon Valley, 215-938-9270. They are not Mopar specific but they know muscle cars and are very good in my experience. They also have a chassis dyno if you're interested. A dyno tune would include optimizing the carburetors I believe. I'd say it's worth a call.