I have an NOS 40712 fuel pump. I think in the 70 engine assembly manual this would translate to 6440712, Does anyone know for sure if this is correct? I think this is the correct pump for most of the 455 engines with the tank return line. Also, This pump was stored since the 70s in a dry climate controlled area. Should i trust it to be good or should i get a new one? I was planning to put it on my 442 only because I had it laying around. I just don't want to put all the money into a new engine to have a dried out pump on it. What are your thoughts?

 

That pump is the correct one for 70w30.

Cheers,

Sam

 

New one.....any of these cars I get that have been sitting gets a new fuel pump ... The old one I keep for posterity...My experience anyway..

Ted

 

Yup, the AC pump stamped 40712 on the flange is the correct 6440712 pump. That's what the original on my car looked like when I removed it, and that's what the NOS one I installed looked like.

I've heard that modern fuels will eventually detroy the rubber surround on the diaphragm. I've never opened up an old pump to see if this is true, but there's at least one honest, reliable fuel-pump rebuilding shop that makes a point of using newer materials compatible with today's gas. Unfortunately, our pumps with their crimped lip are not rebuildable. (Someone please tell me if you know of a shop that does rebuild crimped pumps.)

I've started experiencing fuel-delivery problems again. My NOS pump has been installed for maybe 6 years now. If I isolate it down to the pump, I'll probably use a modern replacement. Originality is nice, but the car's' got to GO!!!

 

I do not know about fuel pumps, but I had Terrill Machine out of Deleon, TX (google it) rebuild the distributor vacuum advance on my '55 Cad, and the device is crimped.

Cannot hurt to inquire of them?

 

I wouldn't trust an NOS fuel pump long enough to install it. Ethanol fuels will destroy it in short order. The last NOS pump I put on one of my Starfires lasted less than 100 miles driving before it started leaking and had ultimately failed by 125. Had to have the car towed home as a result.

I really am considering putting an electric pump on it.

 

I'm leaning toward an electric pump, too. But I desire the original look, so I've got two questions:

1/ Can you keep an original pump in place and push fuel through it from an electric mounted in the back? If so can the original pump serve as the regulator (assuming it's the type with a return line).

2/ Does anyone know of an electric pump which can be mounted inside the tank as part of the send unit?

 

Brian, Spectra Premium makes stock looking tank with a electric fuel pump in it. Don't know if it will pump thru a stock pump though. I have a stock tank from this vendor and they are a very nice, spot on match to the originals.


http://ecat.spectrapremium.com/Produ...cule/000024210

 

Thanks for the suggestion. Unfortunately, the pump is intended for fuel injection, with an output of 85-115 psi. I kinda doubt this would work with a 6-7 psi regulator, but maybe someone knows for sure?

 

The Corvette and Mustang vendors are selling rebuilt crimped pumps. We just need to find out who does the work. It would be nice to get some pumps rebuilt with parts that will hold up to modern fuels.

 

Correct pump # for the AC DELCO 40712 is 6470330.

I have 2 NOS for sale.

 

Brian - I have heard of folks using an electric in series with a mechanical to prime the carb (fill the bowls), so I think the electric will push fuel through the mechanical. Do a google search. Not sure about the regulator part of your question, but I would like to know the answer. I plan to install an electric as soon as time permits.

 

My name is Fred and I do restore these crimped together style of fuel pumps. I rebuild them with diaphragms and valves that are compatible with our current ethanol laced fuels. They get cleaned and replated as original. I am currently working on my seventeenth run of these crimped together style of fuel pumps. I have done over 800 pumps so far. I am planning to begin another run in the near future.

I seem to be the only one in the world currently restoring these pumps. If you Google "crimped fuel pump rebuild" you will find that my name seems to be the only one that shows up although mostly associated with Fords. I am also doing the GM and Mopar versions.

Fred Ballard
28916 Flowerpark Drive
Canyon Country, Ca. 91387-1801
661-251-2362
fredsclassics@hotmail.com

 

Fred - Since you restore these fuel pumps, do you know the answer to Brien's questions?

1/ Can you keep an original pump in place and push fuel through it from an electric mounted in the back? If so can the original pump serve as the regulator (assuming it's the type with a return line).

 

The fuel pressure is regulated by the internal spring in the pump when the pump is functional. Any external pusher pump will bypass that action and raise the fuel pressure according to the pusher pump pressure. Another down side to a pusher pump is that if you have a diaphragm that is compromised by the ethanol causing a leak, the leak will most likely cause a fire as the fuel will spray out through the relief hole for the diaphragm. If your pump is in good shape but unable to flow enough fuel, a pusher pump is acceptable but if it produces a higher pressure than stock, you will need a regulator such as a Holley one. Pusher pumps were the order of the day back in the 60's and 70's when muscle car engines demanded more fuel than a stock pump could deliver.

-Fred-

 

Thanks Fred!

My plan is to install an electric pusher pump to prime my carb bowls after the car has been sitting a while. Switch it on before I start the car. Switch it off after the carb is primed, or the car started. I will probably put a check valve in parallel with the pusher pump to make it easier for the mechanical pump to pull fuel - not sure it is needed, but it seems easy to add.

 

I do not believe that your stock fuel pump will be able be able to pull the fuel through your pusher pump efficiently if it is turned off. I know that can depend on what type of pusher pump that you use but at the very least it will restrict the flow. Your thought of a check valve with a parallel line seems to have merit. Make sure that your pusher pump is not overly high on pressure.

-Fred-

 

How much is it to rebuild an original pump? Also, Do you buy old cores?

 

The price to restore your pump is $220 plus $18 return shipping in the lower 48 states. I do purchase core fuel pumps but as yet, I do not purchase core fuel pumps for Oldsmobiles. If the demand increases, then it is a possibility. Knowing that the cores can be restored would definitely help you sell your cores to someone in need on this forum.


-Fred-

 

Fred, are you still rebuilding these pumps?

 

Thank you for your inquiry.


Yes, I am still doing these pumps and I am in the middle of my twenty third run. I have done almost 1,000 of these pumps so far.


Thanks,
Fred
fredsclassics@hotmail.com