I have recently purchased an older GM vehicle that has had a LS swap done to it.
I am trying to figure out what size injectors are installed in the engine.
I took a close up photo of two of the injectors so I could clearly see the numbers on the side of the injectors.
I see "24" on one injector in the photo and "19" on another.

Is this 24 or 19 mean anything as far as the size of the injector?
The reason I ask is all the other injectors have different numbers on them.
It seems like no two match as far as these number shown in the photo below.


See the "24" on one injector and "19" on the other one

 

probably junk replacements
get new ones and be 100% sure you have perfect working injectors.
if one is a 19# and the other is a 24# thats bad news

 

Those look kinda like stock 4.8/5.3/6.0 truck ones from the early 00's, which are about 26 lbs/hr if memory serves. The fuel rail also looks like a truck one of that vintage. I don't think those stamped #s mean anything. The actual part # should be on the side opposite the electrical connector. You can rotate the injectors the full 360° to check what else is marked on them.

 

I was able to spin the injectors around and get a part number off the back side of each injector.
All eight injectors are 12580681 GM injectors which seems to be for a pre-2009 6.0L motor and has a flow rate of 30.2 lb/hr

 

Yup. Same ones that my 04 5.3 truck has. It's gas only: the flex-fuel ones are different.

 

youre kidding me.
you didnt think to move them before this post?

 

Also I recorded all these two digit numbers off all of the injectors.
I have no idea what these two digit numbers mean though.

Front
27 24
34 19
24 28
30 27
Back

 

I don't either.

I just ignore them. They are useless. Probably something like the last 2 digits of the serial number of the fixture they used to check them, or the employee ID of the inspector, or some equally worthless kind of production data that while perhaps critical to the mfg process, once they leave the factory, no longer has any meaning.

Pretty sure those injectors are about 26 lbs/hr at the standard measurement conditions (3 bar FP) as opposed to LS motor FP (about 3.6 bar).

 

Injector FAQ

 

Those are most likely casting mold numbers. Meaningless for what the part number is. They are for manufacturing control and management.