just to update,i've been searching out my problem for the past few days .i've ck,ed and set timing to 6 degrees btd after cleaning off the harmonic balancer to verify makes properly.after making sure balancer had not slipped and was in proper location ,i proceeded to to check full advance an d found to be 37 degrees.i pulled out  plugs to find a very acceptable light brown color setting flost levels and using a vacuum gauge to sinc air fuel mix.the last thing i found was the electric choke was tied to positive side of coil which may have been disrupting ignition signal.i deleted choke altogether since arizona temp doesn't require a choke.i took the car to a cruise-in last night and enjoyed the car imensely.iwanted to make sure it ran properly before upgrading to the new wiring harness,steering column and gauge pod.i do appreciate the help of the forum and will continue to keep everyone informed fo my progress and hope to assist others.thanks

In your case, the distributor vacuum needs to be hooked up to ported vacuum for normal running as being hooked up to direct vacuum would be part of the surge problem you’re experiencing.  I’m assuming you’ve timed the engine with a light?  If not, then that would be next on the list and also check the advance curve with the light while bringing the rpms up.  Initial timing can be as much as 10-12° with the vacuum advance disconnected while the total timing with the MSD distributor is not expected to exceed 38°.  Total timing may all be in by 3000 rpms depending upon how your particular distributor is set up.  This is something you can verify with the timing light by simply bringing the engine rpms up until the timing advance stops and noting the rpm at which it stops moving.  The MSD distributors have a considerable amount of flexibility for adjustments to the advance curve both in the amounts and the rate and this is something you may have to dive into deeper if the surge at cruise is still an issue after addressing the aforementioned items.

Lorena, Texas (South of Waco)

i just went out and chk'ed the distributor and to my surprise it looked like a billet housing and after pulling the cap i find i have an msd distributor and msd blaster coil, i apparently already have a modern setup.  now is there a special way this particular dist is adjusted or is there another direction i should go in?  by the way i really do appreciate all the input.

As Gary and Doug both mention, the first item to check is the distributor design.  If you have the Load-O-Matic, then it needs to be replaced with the ’57 and up design.  The LOM’s have no centrifugal advance mechanism in them and rely solely on vacuum from the carburetor to make them work.  1956 was the last year for the Load-O-Matics and starting in 1957, they were replaced with the more conventional design that incorporates both centrifugal and vacuum for ignition advancing capabilities.  The modern carburetors such as your particular Holley do not have the internal circuitry to allow the Load-O-Matic distributor to function as originally designed and typically throw too much advance at the engine under cruise situations and no advance at initial take off and under moderate or heavy throttle.  If you have the distributor vacuum hooked up to the intake or to direct vacuum at the carb, then the vacuum signal during cruise situations is intensified which compounds the surging problem you mentioned.

 

The LOM distributors measure about 3½” at their housing while the ’57 and up distributors will measure out at about 3.7”.  The vacuum advance chamber on the LOM distributor will be about 3” O.D. while the ’57 and up distributors will be in the neighborhood of 2½” O.D.  The LOM distributor will have a pair of small springs located above the breaker plate while the ’57 and up distributors will have the advance springs hidden and out of site under the breaker plate.  The LOM distributors used straight breaker points while the ’57 and up distributors use curved points but with you having a Pertronics conversion, this will not be much help in your particular case.  These tidbits may help in identifying which distributor you have. 

 

Once you clarify which distributor you have, then troubleshooting will be simplified.

Lorena, Texas (South of Waco)

 When your engine is under load you're still losing vaccum. Doug is right about changing to a later 57 and up dist. The 56 dist  known as a loadamatic is designed to work with 56 and older carb and vaccum systems that have vaccum even when the engine is pulling under load. The later 570 cfm is designed to use with a later dist that have centrifugal weights that work with rpms. Chime in Ted you and Doug are better at this than me

-Gary Burnette-

it's a stock dist with petronics internals[unsure of spelling];the carb is new holley part number 0-80570;i'm running direct vacuum to the vac advance instead of ported

You don't mention what distributor you have, But if it is not bone stock and matched bone stock '56 carb you probably have no working advance mechanism.  The first thing to do is get rid of the Loadomatic distributor that was last used in '56 and up grade '57 or later dist that has centrifugal advance and true vacuum advance.

If you do have a completely stock '56 Loadomatic dist and carb that were properly rebuilt and matched then you should check the shop manual for the proper vacuum curve.  It will peak at something like 3" at which you should then have the full factory advance. I don't have this vacuum/Advance curve handy but It is in the '56 shop manual.

Doug T

The Highlands, Louisville, Ky.

i have a 56 fairlane 292 fordomatic,all stock with a holley 570 cfm carb and electronic ignition,timing is set at 6 degrees btdc,vacuum at 17".my problem is at cruise,vehicle surges severely,commonly refered to as trailer hitching,also right off idle when taking off it will lay down,but if you get into it a little more it goes pretty well.it just seems to me that the problem is still in the carb.i haven't broke into the carb yet but was wondering if jet size may be the culprit