So I received my FAST fuel rails for my LSXRT intake today. Injectors fit into the rails just fine, I can get most of the injectors in to their spots but some just don't want to. Now I did get my FAST intake used and the previous owner gave me the o rings as well but I'm wondering if I might be better off ordering a new set from FAST.

and yes I did lube them up and I used some clean motor oil and just rubed in on with my fingers around the o rings







factory O rings

 

finally got it but man that was a pain in the ***

 

Best thing for installing orings is STP oil treatment. Doesn't do the motor any good putting it in the oil, but makes orings slip right in lol.

 

What injectors are you runnin?

 

You sure you don't have those rails backwards?

 

looks like the angle of the dangle is correct. I had a hell of a time with ls7 injectors in my 8.1 intake come to find out stock injectors and ls7 ones have a size difference I ripped the plastic nub off the injector pulling it back out

 

the factory truck 5.3 injectors

they are face the right way, the name fast has to be outward away from the engine.

 

When you say factory 5.3 do you mean the regular 5.3 or flex fuel version 5.3 injectors.

 

Regular 5.3, the motor is a 2006 Silverado L33

 

Did you figure this out? And how?

I cannot get my 8.1 marine truck injectors into my LSX-R cathedral intake!?