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Good Afternoon
My question today is, are there any issues with going to a fuel pump with just suction and pressure ports, the one on it now is an OEM
. style pump with the vapor hose connection and is leaking gas from where diaphragm housing joins to cast part of pump .After looking on-line it doesnt look like there are a lot of options for an OEM style pump and a lot of places show they have no stock. With the modifications do I need more than an OEM pump?
Also would like to hear recommendations on a replacement pump if you have one.
The car will just be used as a cruiser, it is a 355 with alum. heads and intake, headers, 650 holley, 4 speed and cam.
Thanks in advance!!!!
The OEM with fuel return line keeps the fuel circulating back to the tank to prevent vapor lock. I would recommend that over one without. This is what you'll probably end up with. Issue I and others have had recently is that the bottom portion is longer than what comes out so lines have to be tweeked a little to fit.
I replaced the original pump with one without the fuel return line. Three times I was stuck in the middle of the road with vapor lock. I replaced the pump with a fuel return line and have never had a problem since. 1974 small block - in Texas.
I have an Airtex pump, part # ATX-41240, an OEM style replacement, that has been sitting in my garage for almost a year. I’ll give it to you if you’re interested. I have no use for it. It’s got about 500 miles on it, one year operating, one year sitting. I had to switch to a bigger pump when I installed NOS kit. Stock replacement, 3 ports.
post pic of your original..if ac on it i seriously would consider rebuilding as mentioned @fake before but have no clue who does this..
usa made unobtainium…
You have two choices. Install an electric pump,,,, then wonder why your carb is being over feed,,,, Then install a fuel pressure gauge,,, find out you have too much pressure,,,, then install a pressure regulator,,,, then wonder why it isn't running right. Then start messing with the carb to correct something, but not knowing what the heck is wrong. Then buy another electric pump that isn't so strong,,,,, ETC ETC ETC. Or install an original style pump and return line.
Agreed on the crap pumps….. For example Carter for whatever reason on a early 70s 454 car think 9 psi of fuel pressure is acceptable, which it’s not. A lot of folks have had problems with OE replacement pumps. The best course of action if you have to purchase a new pump is to pickup a genuine AC Delco pump, but those have been NLA forever. There is no quality control in the the aftermarket OE replacement pumps. Never has been. You might get lucky and get one that functions right, or you might not. I would either have your OE pump rebuilt or swap in something like a Edelbrock 1721.
If you go with a two line pump the transition isn’t bad. Basically you need to:
A. Make sure you have a vented fuel cap.
B. Cap your vent line in the engine compartment.
Will you be more likely to vapor lock the car with a two line pump??? Maybe, but that’s a tough one to call. Lots of guys are running two line pumps with no issue. Original L88 cars were two line only. Things to consider.
Thank You for all the replies, you guys are very helpful. I ordered a new Delphi pump, will give it a try.
I agree with the questionable quality of some aftermarket parts anymore. I am a mechanic by trade and we wont hardly buy any electric parts from the aftermarket anymore. sometimes its hard to get the customer to spend the extra money for OEM.
i tried all of those that were in stock in the last year.
you will find that they are now essentially one to 2 mfr now, carter china or korea delphi..at least within last 12 months..
i even went to napa brand..korea again..and the holes were not big enough to install!!
the rest fit but started knocking..i have a spare just waiting again..even ebay monitor on for anything different..
The original GM part number 6470308 the AC Delco number is 40769. Was used from 1970 to 1972 Corvette except High Performance then all 1973 to 1976 350 engines
1975 fuel pump
