fuel pump

[mopower04]

on my 79 power wagon 4x4 that i'm putting this 440 in I am still not sure what to do about a fuel pump. someone told me i need 1/2 line from the tank to the carb. another person told me to put an electric pump as close to the tank as possible because 440's tend to vapor lock and that would prevent it. Another told me a mechanical block pump would be ok. what is the better way to go as far as a pump for a 4x4 440 with about a 750 or better carb, fuel line size? and about how much pressure should the fuel line be at???? there are so many pumps out there its hard to find one that sounds right. holly, carter, edelbrock, and they all promise something else.... help me!!! lol

[superbee1970440]

I don't think it's possible for one motor to be prone to vapor lock. Vapor lock happens when fuel in your boils, making vapor. Without liquid fuel, the motor stalls. All you have to do is route your fuel line away from heat sources (exhaust & engine block).
The use of a mechanical or electric pump just depends on how your motor is going to be built & your personal preference. Unless you are running fuel injection, or a really high RPM/horsepower motor, run a mechanical. They are so much easier ( no wiring or extra draw on your electrical system) and typically, they are really noisy & get annoying.
The size of the fuel line also needs to be determined by your engines needs. 3/8 would be plenty big for a mild, carbed 440.
Fuel pressure should be 5psi for carbs (in general)

Hope this helps

Sam

[mopower04]

that does help alot. of course in the $$$$ any particular brand anyone would recommend for a mechanical pump? 3/8 inlet and outlet??

[rumblefish360]

A 3/8 line from tank to carb is plennty for a serious HP street engine. An off the shelf Carter HP pump with a 5-7 psi rating will bolt in and do the trick. Nothing else be needing worry.

[cudajon]

Feeding my 494" I was constantly fighting a fuel problem, either to much pressure or fuel starvation at the big end. I put a holley electric at the tank hoping to regulate the pressure through out the rpms (max 6500 feeding two afb 650's). I run a return line to the tank and noticed a drop in pressure at 3000 rpm up. Figured it was the return line so I blocked it. Massive flooding at the carbs, yes I run a regulator (tried several) when coming off a full power burst (both carbs wot) it would gurgle and belch black smoke. Anyway to make a long story shorter. I had changed fuel pumps, added electric, 3/8" fuel line, etc, etc. Problem turned out to be a worn fuel pump shaft. It was almost 1/2" shorter than a new one. Problem fixed. Don't overlook the obvious....

[mopower04]

What is ment by NPT size or say -8 ANP size on fuel pumps and fuel lines? i'm tring to find a mechanical pump for the 440 with 3/8 inlet and outlet but they all say 1/4 unless you look at electric pumps. also is a regulator required on a mechanical pump?

[superbee1970440]

Originally Posted by mopower04

What is ment by NPT size or say -8 ANP size on fuel pumps and fuel lines? i'm tring to find a mechanical pump for the 440 with 3/8 inlet and outlet but they all say 1/4 unless you look at electric pumps. also is a regulator required on a mechanical pump?

NPT is "national pipe thread". I have no idea how NPT is measured because a 1/4"-NPT fitting is about 1/2 inch at the threads. Most mechanical fuel pumps have 1/4"-NPT fittings & the adapters will most likely adapt 1/4"-NPT to 3/8 inch fuel hose.
I can't remember what AN stands for but it is just another way to measure fluid fittings. -8-AN is about 7/16" so that is pretty big. -6-AN should be about 3/8" or 5/16".
Most "street" mechanical will be internally regulated at 5psi unless stated otherwise. So you shouldn't need a regulator, although, it wouldn't hurt anything to have one.

Sam

[pishta]

AN is Army/Navy and it is in 16ths. 8 = 8/16 or 1/2 inch. The measurement is the OD of the rigid pipe that is used in the fitting.

[mopower04]

so if i get a mechanical pump that has 1/4" NPT I can run 3/8" line to and from it? or do i need an adapter at the pump, and if so wouldnt that cause a restriction and defeat the purpose?

[cageman]

Drill and tap the pump to 3/8 or1/2 if your worried, Ive done it, so it cant be that hard. If you dont, just get a single adaptor form someone, that goes from 3/8 pipe to an 6, or 3/8 to -8. On my circle trackers, I run -8 from the fuel cell to the pump, then -6 to the carb. probably overkill, but I have been down the road of fuel starvation before, no fun, kinda ruins your weekend.

[70Barracuda]

I guess its a stock 440? Get 2 pumps. Put one in the truck for a spare. Go to the auto parts store and get what you need. If its 1/4 NPT, get it. Maybe get a steel line, bend to fit with a small piece of rubber. The smaller the better. Carry a spare! Then you wont need it! LOL

[mopower04]

No its not quite stock, and its not quite insane. its a mild truck build. domed pistons, .513/.533lift cam 770 carb, what not, all i'm askin is what is 1/4NPT measure and does that fit a 3/8 line? If not i'll find a different pump.

[pishta]

I had 5/16 line in my 65 and it threaded into the Holley street pump. I dont know what fittings were on there but it was out of the box. And the street pump was supposed to be a warm mechanical pump. Seems to me that the 5/16 line and the 3/8 line had the same OD on the threaded connector that mated to the fuel pump, the 3/8 was just a thin wall connector and the 5/16 was thicker. Make sense?

[Crank]

you can get 3/8 line with 1/4 npt fine and corse threads.so spend a quarter and get a pipe plug and see what size it is i wouldn't drill and tap because a pipe tap is tapered unless you use a pipe tap,and a pipe tap reemer.before you tap.

[ttraut@unlockit]

I bought a fuel pump for my 440 and had questions like yours because my adapter fittings leaked.

Check out the thread at
http://www.moparchat.com/forums/showthread.php?t=92521

Bottom line, buy the pump that works and then get the fittings that work. AN, NPT, and flare fittings all are important to know here!

Terry