I built my lt1 to a 383 and I put in 36 lb objectors, I have a walboro 255 pump to put in but I want to try and first start the motor with the stock pump, will the stock pump hold up to the large objectors? will it make a difference if i had the computer tuned for the 255 pumpk? thanks in advance

 

The 36lb injectors will not require any more fuel for start up, idle and normal cruising than the stock injectors. I don't see any problems under low engine loads. You will need the extra fuel during WOT situations. You don't tune the PCM for the fuel pump. The PCM looks at the the injector flow rate to insure the AFR is correct. If you have larger GPH injectors the PCM lowers the amount of time the injectors are picked and you use the same amount of fuel as stock 24 lb injectors. However when you start sucking large amounts of air under load the PCM increases the injector duty cycle and they start pouring fuel into the cylinders. That's when you will need a larger fuel pump to make sure the fuel pressure stays where it should be. Don't quote me on this, as it's all hearsay, but a stock FP 150-190 liter/hr will probably support up to about 350 HP , I've read the 250 ltr/hr will get you near 500-550 HP mark. Maybe someone with some actual numbers can chime in ....