It would take me hours to list everything in my motor, So here is the short of the long......
Chevy 350, stnd bore
Forge 8.5-1 pistons
lt1 rods
Fully ballanced and blue printed
Full ARP studs, everywhere!
Eddlebrook Alum performer RPM Heads
1.5 full rollor rockers
Ported Tpi lower intake and siamezed runners
1000 cfm throttle body
D1-sc Procharger
Currently 36lb/h injectors
Accel DFI gen7

My question is what size injector should i really be using? I plan on getting this car fully dyno tuned within a couple months, so i want everything ready so i can maximize tune time. The reason this question comes up is a buddy of mine just picked up a procharge kit for his 09 mustang, and it had somthing like 50lb injectors. Just want to see everyone elses opinion on injector size.

How much horsepower do you plan to make? If you have a general idea, enter that number into an injector calculator and it will calculate the size you need. If the resulting value is in between injector sizes, it's a good idea to round up to the larger size.

Or, you can do what I did and talk to Jon at fuel injector connection. Let him know your combo and goals and he will be able to recommend the right injector.

Well thats the question, idk how much power im gonna be maken, but i guess it would be anywhere in the range of at least 300 to 450 realistic.

The calculator at 500 flywheel hp said i should use a 42lb/h injector. I have 36lb/hr right now so i think i should be safe for now.

Boost referenced regulator? For say 42psi base fuel pressure, 10 psi boost should give 52 psi which will make a 36 lb injector flow like a 40lb injector.

If your in the 400whp range, 36's will work fine. I had 42's on my 383 which made 400whp and it was overkill.

Thats what i figured. All my buddies in ther lil 4cyl dingdy dings sware i need way bigger injectors, but the current tune i have and the data log i come up with shows them to be just fine. Thats with my fuel regulator cranked up to about 54 psi or so.

4 bangers have half the injectors we V8's have, so they need almost twice as much injector for same power.

Good point!

52 psi of fuel pressure compensates for the boost that is trying to push the fuel back. therefore the 36lb injector flow will not be changed.

Hmm, i thought it would increase the pressure to make the injectors flow more for the added boost pressure but I guess I'm getting that confused with an FMU? I didnt think manifold pressure would work its way back thru the injector and cause a drop in fuel pressure.

not really a drop in fuel pressure. lets say your running 42 psi of boost and 42 psi of fuel pressure . Now when your injector opens fuel will not come out because your boost pressure = your fuel pressure.there needs to be a pressure difference in order for your injector to work.

FMU will make the injectors flow more because they increase the fuel pressure more than required.

That makes sense, I didnt think of it like that but your right thats exactly how it works.