MaroonMonsterLS1

Ok, so i've done the math, used the search, and am still not 100% sure on what to do.

Trying to make about 350-380 wheel hp out of a 5.3. It will have gen 4 rods and flat tops, ported heads, 226/233 cam, truck intake. Shooting for about 11:1 compression. Going to upgrade to arp rod bolts and spin it about 6800. Will have a walbro 450 in tank and will be using the corvette fuel filter/fpr combo.

I get confused when looking at different injector combos and what people say they will handle. For example f body ls1 injectors (28.8@58) have been said to handle 400 wheel at 90% duty cycle in the real world, but injector calculators tell a different story. The calculators say there's no way in hell. So, i'm coming to the experts here.

I need to pick an injector size. I'm going to pick up a set of heads about 3 hours from me on a killer deal, and if i'm driving that far, i'd like to pick up the injectors if they will work because i'll be able to get those for super cheap as well. The part out is from an 08 pickup. 5.3 I'm assuming it has the 1250681 injectors. From all of my reading, they are supposed to be 30lb/hr @58psi. This translates to about 27 @43.5 psi right??

If so, is that going to be enough to meet the goal? Especially at that many rpm?

If I get lucky and it was a flex fuel truck with the 12594512 injectors (36@58) or 31@43.5, these should certainly support about 400 wheel right?

I'd just like to feel a little more confident before i pull the trigger on a set of injectors that won't be able to handle the needs.

JoeNova

I did an O4 GTO with an LS1 that made 388whp on stock injectors.

Btw, vette filter/450 is a bad combo. The pump overwhelms the filter and it runs at an extra 10 PSI or so at idle.

You sure you need a 1000 HP fuel pump for your 350whp combo?

MaroonMonsterLS1

I'll also be spraying about 200-250 on the setup and wanted the fuel pump to be the least of my worries. A 255 is like $110 and a 450 is only 30-50 bucks more. I figured why not.

What would you recommend for a regulator and filter setup? The corvette combo seemed to be the simplest and most budget friendly.

JoeNova

Truck intake?

Get return style rails and run the stock truck regulator, or go with a 340 lph pump with the vette regulator.

MaroonMonsterLS1

Ok, the engine that i'm using is a 99. So it should already have the return style rail correct? 99-02 were return style right? The truck i'm going to get parts off of (heads and injectors) is the 08. sorry if there was confusion. In this pic, the large line is the supply and the small is the return correct? Can I just use this factory setup with only a filter and not the corvette setup?

JoeNova

I can't view attachments, but you have it right. Small line is the return. You can just run an inline filter.

MaroonMonsterLS1

So I got lucky and they were flex fuel injectors. p/n 12594512 injectors (36@58) or 31@43.5!!! Should be plenty to handle my little setup.

I have a few questions about these. They are about 1/4 in taller than the stock 99 injectors, but the o rings seem to be the same dimensions. Can I toss them in the intake and 99 rail with just a spacer under the rail mount?

Also, on a side note, will the factory 5/16th feed line on a foxbody be able to support that much fuel flow? I'm betting it could support the motor but will it become a problem when spraying?