55lb injectors on stock fuel pump
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Senior Member
Joined: Dec 2003
Posts: 758
Likes: 1
From: Ontario, Canada
Car: 1988 Pontiac Trans Am
Engine: 5.0L Fuel Injection
Transmission: Automatic 4speed /w OVerdrive
55lb injectors on stock fuel pump
If I were to upgrade to the 55lbs injectors on my throttle body...would I need to replace the stock fuel pump as well or would the stock pump be ok?
Senior Member
Joined: Dec 1999
Posts: 770
Likes: 0
From: San Antonio, TX
Car: 86Z/92 RS Camaro
Engine: 357 vortec finished. need tuning
Transmission: Still works
Axle/Gears: need 3.73
Color code
Application
Flow rate
Part #
Black/White
1-3/8" bore 2bbl, from 2.8l truck
???
GM 5235430 *RPD
Yellow/Blue
4.3L
???
GM 5235203 *RPD
Green/White
5.0L
40 lb/hr
GM 5235279 *RPD
Orange/Black
5.7L pickup
55 lb/hr
GM 5235206 *RPD
Yellow/Brown
5.7L Cop Car
65 lb/hr
???
Application
Flow rate
Part #
Black/White
1-3/8" bore 2bbl, from 2.8l truck
???
GM 5235430 *RPD
Yellow/Blue
4.3L
???
GM 5235203 *RPD
Green/White
5.0L
40 lb/hr
GM 5235279 *RPD
Orange/Black
5.7L pickup
55 lb/hr
GM 5235206 *RPD
Yellow/Brown
5.7L Cop Car
65 lb/hr
???
Joined: Jan 2005
Posts: 10,450
Likes: 508
From: Hurst, Texas
Car: 1983 G20 Chevy
Engine: 305 TPI
Transmission: 4L60
Axle/Gears: 14 bolt with 3.07 gears
That chart is somewhat out-dated. The STOCK injectors in the 305 TBI that I pulled off of a 305 truck were 55 lb/hr on a flowbench. Stock 350s are 61 lb/hr.
2.8 = 36 lb/hr
4.3 = 46 lb/hr
5.0 = 55 lb/hr
5.7 = 61 lb/hr
5.7 High Flow = 68 lb/hr
5.7 Vortec Van = 74 lb/hr
7.4 = Various ratings depending on year/application
2.8 = 36 lb/hr
4.3 = 46 lb/hr
5.0 = 55 lb/hr
5.7 = 61 lb/hr
5.7 High Flow = 68 lb/hr
5.7 Vortec Van = 74 lb/hr
7.4 = Various ratings depending on year/application
Senior Member
Joined: Dec 1999
Posts: 770
Likes: 0
From: San Antonio, TX
Car: 86Z/92 RS Camaro
Engine: 357 vortec finished. need tuning
Transmission: Still works
Axle/Gears: need 3.73
Before I did the 350 vortec swap on my 92 RS w/305, it had 5235279 on the injectors. Anyone else TBI land w/stock 305 have the same injectors?
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Senior Member
iTrader: (-1)
Joined: Oct 2008
Posts: 321
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From: New Milford CT
Car: 1991 Trans Am
Engine: 305tbi to 350 carb'd
Transmission: 700r4
Axle/Gears: Stock
Re: 55lb injectors on stock fuel pump
i have new ones in my firebird and they have a red top on one side it says
RI279 and on the other side it says 7124? i have no idead what thats telling me?
RI279 and on the other side it says 7124? i have no idead what thats telling me?
Joined: Feb 2006
Posts: 767
Likes: 10
From: USA
Engine: 350 TBI W/all Ultimate TBI Mods
Transmission: 700R4 Stage 4
Axle/Gears: 9 Bolt 3.27
Re: 55lb injectors on stock fuel pump
I have a bunch of 5206, 4304, 5231 injectors and have had them all flow tested, etc.
5235206 typically flow at 650cc/min to 700cc/min @ 1bar which is 14.7 psi. This means that a 5206 (stock 5.7L) injector ranges in the low 60's for lb/hr.
Increasing fuel pressure (if pump can handle it) will increase flow rate and HP. Most stock fuel pumps dont do well about 14-15psi especially at WOT, etc.
I have some 5235206 injectors that flow at 720cc/min @ 14.7psi
So.....
5235206 typically flow at 650cc/min to 700cc/min @ 1bar which is 14.7 psi. This means that a 5206 (stock 5.7L) injector ranges in the low 60's for lb/hr.
Increasing fuel pressure (if pump can handle it) will increase flow rate and HP. Most stock fuel pumps dont do well about 14-15psi especially at WOT, etc.
I have some 5235206 injectors that flow at 720cc/min @ 14.7psi
So.....
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