I need some advice as to what lb injectors I should run in my lt1....020 over,cnc ported stock heads,edelbrock intake full ported,comp cam 242 intake and 252 exhaust @.050,comp 1.6 rrs,pacesetter lts,borla exhaust,4l60e trans w/3500 stall,3.73 gears,walbro 255...The will be going to be dynoed in the next few weeks and I need to order some injectors before then..

 

36#'s should be plenty good for what all you have listed there.

Just make sure you get a good brand. No Accel or Venom.

 

What was your hp target when you bought that cam? I can't guess what your output will be so I'd always go bigger....42#/hr will support much more power than you're likely to make snd the PCM can adjust to compensate if they're oversized...

 

I like Fred's formula. Take your estimated flywheel HP and multiply it by .07 to get your suggested injector sizing using a BSFC of .5.

FWIW, I have 42# injectors with a MUCH smaller cam and they see peak DC around 70%, so I'm thinking 36#s might be a bit on the small side.

 

Target rwhp was 425..that was before i changed from a 6spd to a 4l60e..After 5 failed back surgerys and nerve damage to my left side,I decided to keep the car a make it an auto.I was running a spec 3 clutch at the time,I could have probably gone with a less aggresive clutch and been ok..live and learn.

 

If that's the case, 38's will work. I'd still go with 42's just to be on the safe side.....

 

Would 42lb Red Tops be a good choice?

 

You have to use flywheel HP to determine the required injector size, not rwHP. The 0.07 factor suggested above results in the minimum recommended size, and is based on a BSFC of 0.476 #/HR/HP and an 85% maximum duty cycle.