Will the oem fuel pump be adequate with a ZZ6 crate motor?
04-29-2018, 12:23 PM
#1
Pro
Thread Starter
Will the oem fuel pump be adequate with a ZZ6 crate motor?
The new fuel pump that comes with my ZZ6 is a non return style pump. It just has an “in” from the tank and an “out” to the carb. Also. The “out” is located much differently than the oem pump so using my stock hard line to the carb is not in the cards.
Alrernatively, I could just get a new oem 1975 pump. It bolts in and obviously hooks right up to the oem feed/return lines. Plus I can untilize the oem hard line to the carb. I’d have to mod the carb side of the oem hard line so it connects to the 6an style fitting I have for my Holley but that should be a snap.
Does an oem 1975 fuel pump supply enough juice for a ZZ6 and it’s 405 wild horsies?
The carb is a 770 cfm Holley. According to the interwebz the oem pump flows 38.3 gph.
Alrernatively, I could just get a new oem 1975 pump. It bolts in and obviously hooks right up to the oem feed/return lines. Plus I can untilize the oem hard line to the carb. I’d have to mod the carb side of the oem hard line so it connects to the 6an style fitting I have for my Holley but that should be a snap.
Does an oem 1975 fuel pump supply enough juice for a ZZ6 and it’s 405 wild horsies?
The carb is a 770 cfm Holley. According to the interwebz the oem pump flows 38.3 gph.
Last edited by Kie; 04-29-2018 at 01:10 PM.
04-29-2018, 02:00 PM
#2
Race Director
oem MIGHT WORK BUT FOR 69 BUCKS YOU CAN GET THE Carter Street Super Mechanical Fuel Pumps M6900 FLOWS 120GPH, THAT'S WHAT i HAVE ON MY 600HP SMALL BLOCK 
04-29-2018, 03:17 PM
#3
Drifting
Member Since: Feb 2007
Location: Pearland Texas
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St. Jude Donor '09
The new fuel pump that comes with my ZZ6 is a non return style pump. It just has an “in” from the tank and an “out” to the carb. Also. The “out” is located much differently than the oem pump so using my stock hard line to the carb is not in the cards.
Alrernatively, I could just get a new oem 1975 pump. It bolts in and obviously hooks right up to the oem feed/return lines. Plus I can untilize the oem hard line to the carb. I’d have to mod the carb side of the oem hard line so it connects to the 6an style fitting I have for my Holley but that should be a snap.
Does an oem 1975 fuel pump supply enough juice for a ZZ6 and it’s 405 wild horsies?
The carb is a 770 cfm Holley. According to the interwebz the oem pump flows 38.3 gph.
Alrernatively, I could just get a new oem 1975 pump. It bolts in and obviously hooks right up to the oem feed/return lines. Plus I can untilize the oem hard line to the carb. I’d have to mod the carb side of the oem hard line so it connects to the 6an style fitting I have for my Holley but that should be a snap.
Does an oem 1975 fuel pump supply enough juice for a ZZ6 and it’s 405 wild horsies?
The carb is a 770 cfm Holley. According to the interwebz the oem pump flows 38.3 gph.
Last edited by redcruz1120; 04-29-2018 at 03:18 PM.
04-29-2018, 03:38 PM
#4
Le Mans Master
I rebuilt/upgraded the OEM L-82 in 2014 in my 78 into a 450 Gross HP engine with 10.2:1 compression. I installed Aluminum AFR heads, and roller cam making considerably more Gross HP than a ZZ6. I installed a new stock AC fuel pump for a Gen1 SBC on the new L-82 355 and have had zero fuel issues.
04-30-2018, 02:24 PM
#6
Race Director
Very few fuel pumps ever approach their max flow. At the drag strip or other race track is about the only time. At full throttle you are gonna lift up inside of 10 seconds. Barely empty the float bowls in that time.
04-30-2018, 10:55 PM
#7
In 2014 I went through the exact same issue with my ZZ5 on my 1974 stingray and did just that what you are talking about. I bought a OEM A/C Delc pump and did just what you have in mind. It ran as expected and not once did I have issues with it as far as fuel starvation. Earlier this year I converted my ZZ5 to Fuel injection and had to do the swap over to electric .......Good luck
04-30-2018, 11:20 PM
#8
In 2014 I went through the exact same issue with my ZZ5 on my 1974 stingray and did just that what you are talking about. I bought a OEM A/C Delc pump and did just what you have in mind. It ran as expected and not once did I have issues with it as far as fuel starvation. Earlier this year I converted my ZZ5 to Fuel injection and had to do the swap over to electric .......Good luck
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redcruz1120 (05-01-2018)
05-03-2018, 02:45 PM
#10
I have a 355 with roller cam, AFR heads and lots more, 385 HP at the wheels. I had a $20 auto parts store pump that would not keep up with the engine at the track. I changed out to the OEM AC Delco pump and have no problems at all.