Clay -

We are hoping that the maximum advance (initial and centrifugal summed) adds up to something in the neighborhood of 36°-38° - with no vacuum applied. If it would all be in by say 2700-2800 rpm, you would enjoy some increased low end torque and avoid (most) problems with bad gas causing a knock on acceleration (with low/no vacuum advance).

The Pertronix "Ignitors" that are mounted on a swivel plate (to provide vacuum advance) must ground through the plate (hence the concern about retaining the old braided strap used with points) and then through the distributor body back to the block. Installing a "ground extension" that goes from the distributor "point plate" clear to the block is a good idea because every OHM that uses up voltage on the way to the block -eats coil power. 

Because this problem occurred over time - and the engine was still firing - I doubt if it shifted time. It is more likely a carb problem. What concerns me is that it looks like your builder utilized one of the new style Holley "non-adjustable float" versions of the 600 cfm carb. Like maybe P/N 0-80457S or something like that? Most of us are familiar with the Holley external adjustable float bowls - and know what to do with them but I don't have any idea what the design scheme of the the new carb is. Older versions of this arrangement had to be set with a guage - after you disassembled the carb - a horrible set-up - but cheap. The presence of alcohol in the "new" gas may be working on the needle material - Viton - and making the setting unstable. 

 
 Steve Metzger       Tucson, Arizona

Steve,

The ground braid is intact inside the distributor. I could add a ground wire fron the distributor to the block to assure a good ground.

When I get home this weekend, I can try the centrifugal only advance and see where it tops out at.

I note that the carburatort will have to come apart to check the floats. And, if I take it off the car to do so, I may just replace it with something more current. I have a question in at the Holley technical department to see if there is a direct or near direct replacement. The list a 570 CFM version with externally adjustable floats, but it is dual feed so I would have to re-do my fuel feed line. that would not be the end of the world.

This begs another uneducated question: Just how reliable or otherwise are the stock Ford mechanical fuel pumps?  Do many of you either supliment the mechanical with an electric or would using only an electric be a popular option?

During last nights practice run, smashing the pedal at ~50mph the car just lost all power. I let my foot off the gas and pulled off the expressway only to have it pick power back up like nothing had happened. It only did this once, but here again, the trust factor is compromised.

pops (AKA) Clay

'56 Thunderbird

Probably the best all around replacement carb has proven to be the 390 cfm Holley with vacuum secondaries and electric choke. Several guys have special ordered a 400 cfm duplicate of the old '57 Ford carb from them but I don't know the numbers involved. I believe your carb could probably be quickly retro-fitted with adjustable side-hung bowls if they were available to you - it should be a straight forward exchange from what I've heard. Won't require new fuel line plumbing.

The 600 cfm carbs will behave just about exactly as you described out of the box - the auto trans fails to downshift and the carb opens the front holes to atmosphere - at zero vacuum - and she just flat quits. Using the Holley "black" spring in the vacuum secondary housing is a good step toward getting things under control. A 600 cfm carb is just about too much for a daily driver and the stiff black spring will tend to make the carb act more like a big two barrel.

Are you utilizing the vacuum pump style of fuel pump - with the two vacuum ports on the top - to operate the wipers? If not, the FE (352/390/428) engine fuel pumps fit right on the Y block and are much cheaper to come by. Mine has the pump from a 428 Police engine with minor plumbing changes - it will feed 300+ HP without too much difficulty.

 
 Steve Metzger       Tucson, Arizona

Clay

Before you get too deep into replacing the carb do some trouble-shooting and find out what is wrong. If it is the secondaries opening at 50 as you step on the gas ( I doubt this is it) you can check by disconnecting the linkage from the secondary vacuum diaphram to the carb and drive a what is now a straight 2BBL and see what that does at 50.

One of the things that happens when you floor the car at 50 is the fast loss of vacuum advance and the plate inside the distributor snaps back. Recheck that ground strap.

Steve is right 390 or 465 is the better choice, however I have a 600 on mine and I have it working well, It will only flatspot if its smashed to the floor real fast at standstill. He's how mine is set.

"Just an update for anyone wth the Holley 600 situation... I am running 64 main jets and have gone up to a 35 squirter and am using the heavy "blue" cam for the pump [aftermarket one]which I  can only get on no. 2 possition. This is working well and I dont need to much throttle to get her going, I have the brown spring from memory for secondaires [other than the very light springs all should be ok as the secondaries would hardly open anyway] . I do have a PCV setup. This is on a B manifold "

bare in mind I am in Australia I dont know how much better our fuel is?

Have you adjusted your float levels yet?!



"Came too close to dying to stop living now!"

I cannot thank ALL of you guys enough.

Inspite of myself, I think you are going to get me on the right path sooner than later. Your collective sage advice is registering albeit sometimes it takes a complimentery hammer blow to go with it.

If I made a shopping list for the existing 600 cfm carburetor, would it include more than adjustable float bowls and larger secondary jets, and a rebiuld kit?

pops (AKA) Clay

'56 Thunderbird

Steve,

The fuel pump is the type with two vacuum lines on it. One is plugged since I have electric wipers. The other appears to go to the back of the manifold for manifold vacuum. What is the rationale for plumbing the vacuum wipers via the fuel pump and not direct from the manifold?

pops (AKA) Clay

'56 Thunderbird

The vacuum booster on the fuel pump was originally designed to insure additional vacuum at the wipers during acceleration.  If you’ve ever driven a vacuum wiper car in the rain without the booster pump,you'll find that the wipers crawl to a stop under acceleration or going up a hill.  The booster pump helps in this situation.

 

Seeing as how you’ve converted to electric wipers, then simply run a piece of vacuum hose in a ‘U’ connecting both ports on the vacuum booster.  This will keep the dirt out of the booster diaphram while also insuring that the booster pump internals are not being stressed by having the inlet/outlet ports individually plugged.  Be sure to plug the intake manifold connection that originally went to the vacuum booster pump as that’s a potential miss or hesitation if it leaks vacuum within the pump.

Lorena, Texas (South of Waco)

you should be able to get a rebuild kit , it wouldn't hurt to have one. But There are a few different types .. some carbs have centre hung bowls and there is two different types of gaskets for the metering plate etc.. Does your carb have the little sight plugs in the side of the bowls? Gonna need to play around a bit with it. I do think you need to adjust your floats first just to make sure, thats easy cost nothing.. 



"Came too close to dying to stop living now!"

Rob - There is an earlier photo in this thread that shows the "non-adjustable" fuel bowls - they will have to come off for access. I'm thinking that if the setting has changed unexpectedly (and it worked before) - something is "afoot". Either goop in the bowl from manufacture (came loose from a hiding spot) or bad gas has done some evil to the needle and seat.

Clay  - Take a good look at the Holley web site and see if there are specific intructions for your carb - the "list number" should be on the front of the choke horn - driver side. Its always a good idea to have some replacement gaskets in hand - even if the carb is supposed to have come with the "no-stick" / re-useable type. If you remove one of the lower front bowl screws and use a little catch basin / cup, the primary bowl fuel will drain into it without soaking the engine. A look-see / cleanup / reassembly will be reasonably quick - and as Pete says, won't cost a new carb.     

 
 Steve Metzger       Tucson, Arizona