Fuel pump question
 

Is there any difference in factory GM fuel pump outputs or pressures.I have built a street performance 454 with 400-450 horse and used a 74 454 block and a 750 Holley and was wondering what fuel pump to use.I am trying to keep it stock looking but was'nt sure if a LS6 or Vette tri power pump had more output than the average GM pump? Also thought maybe they were to big to use without a return line since the heavy hitters in the later 60's had a return line .I am putting the engine in a 76 Malibu and it has NO return line.Any knowledge on this would be appreciated,Thanks Duane

Re: Fuel pump question
 

The Holley carb'd cars didn't have return lines...the Quadrajet cars got those. We run the standard big block AC pump on our Camaro, and we're putting out around 430+ HP at the rear wheels...last summer I swapped in a hi-flo Carter mechanical pump, and noticed no change...

Re: Fuel pump question
 

NUF SAID on pumps,but why did the quadrajets only get the return line,and did they use the same pump as the Holleys that didnt get the extra line?

Re: Fuel pump question
 

Any idea what that part number is for the AC pump you use?Id appreciate it,Thanks

Re: Fuel pump question
 

My low mile all original ls6's fuel pump has the return line.I believe early ls6's did not have the return line.My car is a june car.

Re: Fuel pump question
 

I saw a July LS-6 car that had a return line as well. I just assumed it was an LS-5 car. Is this change documented?

Re: Fuel pump question
 

DSYenko,The part number could be 1 of 2.73-75 Chevelle 454 4" from bottom to mtg holes #6472381.73 Chevelle 454 4.5" from bottom to mtg holes #7470761.These are OE applications so anything is possible.Hope this helps.
Kendall

Re: Fuel pump question
 

DS: ours is the stock 396/427 AC replacement, available from our sponsor above (D&R Classic Automotive)...not near as fancy as what a lot of the guys are running, but it carries our fat @ssed Camaro through the traps at 113+...

Re: Fuel pump question
 

Rob Thanks I will contact them and tell them i want what you have unless you have the number right off hand?
Thanks again

Re: Fuel pump question
 

I believe this would be it, but when you call, make sure this is for the solid lifter big blocks (read: Holley cars):

http://www.drclassic.com/catalog/Cam...el/S00021.html

Re: Fuel pump question
 

Hate to drag this on and on but this pump does not have the return line correct??

Re: Fuel pump question
 

I looked again, and I'm not sure that's the right link...call 'em up, and tell 'em you want the pump for a '69 L78, which will NOT have a return...they also list a repro pump for a ZL1, and have a picture of it, so you could go that route if you wanted...

Re: Fuel pump question
 

Thanks again

Re: Fuel pump question
 

the chevrolet heavy duty parts list has the following part listed as a high capacity fuel pump. has anyone used this part #

http://www.sdpc2000.com/catalog/1037...-Fuel-Pump.htm

what is the difference between this number and the stock AC or high performance L-88 ZL-1 or any of the 375 hp pumps?
mike

Re: Fuel pump question
 

The pressure range of this pump and the L72, L78 ETC.should be the same- --You can rotate this one though to fit application---------------

Re: Fuel pump question
 

joe,
did you look at the picture of the pump? i'm curious how you would rotate the pump? is the picture not what the actual part# looks like? it is part#6415748. i'm curious if anyone has actually used that pump. what would the actual fuel pressure be with the engine warmed up? how mant gph? i got the number out of the "how to hot rod big block chevies" it is an older publication. thanx again mike

Re: Fuel pump question
 

mr ds yenko,
you might want to check out this thread

https://www.yenko.net/ubbthreads/showflat...=true#Post94010

Re: Fuel pump question
 

I just looked up that part # 6415748 in a Chev. Power catalog---And it states---This high-capcity pump has a removable lower housing which can be rotated to position the inlet and outlet fittings as required by the chassis and engine installation--------------

Re: Fuel pump question
 

I don't know if this helps,but I have the Stock AC #40727 Fuel Pump on my L-78 Chevelle,which resembles the one you show.
It recently tested out at 5-8&1/2 PSI @450-1000RPM.
Volume was 1 pint 30-45 sec. @ 700 RPM.

Re: Fuel pump question
 

It's amazing how much thought and effort it takes just to decide what fuel pump i need to order!This is about as hard as ordering a cam! https://www.yenko.net/ubbthreads/imag...s/confused.gif

Re: Fuel pump question
 

That photo rat tuned showed does say it's rebuildable--so the housing should come apart---So check it out---With your 750 Holley--Rob's --Rick,s --or the one in the photo are plenty ---You're lookin for at least 4psi at wot ----IMO

Re: Fuel pump question
 

Any of those AC pumps will be just fine for your application, DS...no need to spend the extra money for a monster pump for a mild application as it will only eat horsepower...

Re: Fuel pump question
 

i have a day 2 type 69 ss 396 chevelle. i'm running a 10-1 454 with holly 750dp, 10" conv, xtreme274H cam, 4.10 gears. the fancy headers won't allow a bigger pump body(too close to header)with the stock replacement carter pump it feels like its nosing over at my shift point(5800-6000). you guys think the the #6415748 with a lightweight pushrod might help? also has stock 3/8" fuel line. thanx mike

Re: Fuel pump question
 

RT: Carter makes a good pump, and that's a fairly mild combo...a lightweight pushrod *might* help, but I'd look elsewhere...like maybe floats or filters or the sock in the tank...and are you sure it's fuel that's causing the nose over, and not like lifter pump? The stock 3/8" line is plenty for your app as well...the engineers at Chevy had lots more education and put lots more time into this then we'll ever have...no need to over complicate things!

Re: Fuel pump question
 

Rob is right , do the easy things first all gas filters--gas flow test --I had a similar problem --Turned out my tach was off hundreds of rpms, and I was over shooting my shift pts---If every thing checks out------ get on a dyno and do a complete basic tune--checking as you go--At least you will eliminate the things that are working----If that nose -down feeling is happening right from the start--Rob could be right about the valve floating---------But make a simple check list and follow it thru---I'm sure you're doing this anyway---Just a Gremlin ( https://www.yenko.net/ubbthreads/imag...emlins/mad.gif)--- somewhere------------------

Re: Fuel pump question
 

thanx guys, i REALLY need to drop the original gas tank and sock. it appears it has never been done. when the tank drops below 1/4 it just doesn't behave quite right. everything else has been inspected and/or replaced. mike