• To ALL forum users - As of late I have been getting quite a few private messages with questions about build ups here on the forum, or tech questions about your personal project. While I appreciate the interest, sending me a private message about these topics distracts from, and undermines the purpose of having a forum here. During the day I wear many hats as a small business owner-operator and I work tirelessly to provide the absolute best service possible to you, our valued customer. When I created this forum I rounded up some of the best minds I knew so that any tech question you might have could be asked and answered by either myself or one of my highly experienced moderators, this way the next time this same question is asked the answer can be easily found and utilized by the next IH enthusiast having the same question. This allows me the freedom to run the day to day operations of the business and minimize the impact to shipments and shop activities that these distractions can cause. It is of the up most importance for me to complete the daily tasks in order to best take care of you our customer, all the while providing you a forum to get the level advice and input you have come to expect and deserve from the premier IH shop in the country.

    So with that I ask that anyone with a question about one of our build ups or a general tech question to please use the forum as it was intended. I am absolutely available by telephone to answer your questions as well but at times may direct you back to our website to better field your question or questions. Most other private messages I will be glad to answer for you.

    Thank you for your understanding.

    Jeff Ismail

GM Injector#/application/flow rate


Active member
GM TBI Injector#/application/flow rate

I found this chart useful.
TBI throttle body and injector information ( link)
these injectors are rated at the pressure used by the factory, about 13 psi
engine | bore ~~~|FI color| flow ~~~| part #
2.8l~~ | 1-3/8 ~~|blk/wht |33 lb/hr |gm5235430*rpd
4.3l~~ | 1-11/16 |yel/blu |45 lb/hr |gm5235203*rpd
5.0l~~ | 1-11/16 |grn/wht |40 lb/hr |gm5235279*rpd
5.7l~~ | 1-11/16 |orn/blk |55 lb/hr |gm5235206*rpd
cop car
5.7l ~~|1-11/16 ~|yel/brn |65 lb/hr |17084327-acr
late big block pickup
7.4l ~~| 2" ~~~~~|blu/blk |80 lb/hr |gm1708430*rpd
big block pickup
7.4l ~~|2"|drk red/drk blu|90 lb/hr|gm5235231*rpd

edit... Bill this is what I found for flow rate, seems odd the 4.6 is higher then the 5.0
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Bill USN-1

F.I. Moderator
Thanks for the info.

Here's the flow rate listed for the sbc tb. From flow tests 1.0

stock 4.3/5.0/5.7 2bbl TBI complete -- 574.1 cfm (dry)
stock 4.3/5.0/5.7 2bbl TBI w/o injectors -- 584.7 cfm
Last edited:

Bill USN-1

F.I. Moderator
When trying to determine injector size and flow rates and bpw and changes in fuel pressure...

Here's a couple math spreadsheets that allow you to punch in the variables to see what size injector at what psi will produce a support a specific hp and will calc the bpw for you. The bsfc is the real variable in debate for a stock IH motor.
injector sizing
The ms manual also has it all laid out.
ms injector info