LM7 383 Build Up

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So even if my motor didn't need as much fuel as the 36# injectors can deliver my tuner can make them deliver less fuel? or how does that work?

[pl4yboy]

So even if my motor didn't need as much fuel as the 36# injectors can deliver my tuner can make them deliver less fuel? or how does that work?

They have what is called an injector duty cycle. Just means they wont have to work hard to deliver enough fuel if they're too big.

[Sleaper]

You will need to have the tune done immediately if you go to bigger injectors. Probably won't be drivable and you wouldn't want to! The 42's that Nelson sells are a direct swap for the stockers. I would buy the 42's, take them with you to your tuner, swap them out and have your tuner adjust for them. Or, order the injectors and a mail order tune from Nelson and be done with it.

It gets technical but just because you have a larger fuel pump doesn't mean you are getting enough fuel. If the injectors aren't big enough to deliver the extra fuel needed, then a Walbro is useless. The opposite applies as well regarding larger injectors and too small of a pump. The injector duty cycle (IDC) mentioned above, is basically the capacity of your injectors. Once you get close to the 85%-90% mark, it's time to upgrade the fuel system. For example, the 24# may be at 90%, 36# may be at 60% and the 42# and 45% (not real percentages, made them up for arguments sake). All would work but the stockers are maxed, the 36# are fine and the 42# give you room to grow. The tuner is who controls the IDC and how much fuel is commanded.

Widebands are a nice tool to make sure you aren't running lean.

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You will need to have the tune done immediately if you go to bigger injectors. Probably won't be drivable and you wouldn't want to! The 42's that Nelson sells are a direct swap for the stockers. I would buy the 42's, take them with you to your tuner, swap them out and have your tuner adjust for them. Or, order the injectors and a mail order tune from Nelson and be done with it.

Thats sounds like a good plan. Should I be able to safely run the stock injectors until I can get it tuned with the larger injectors?
So I am guessing that swapping eight injectors on this vehicle doesn't take much time?

Oh and can some one point me to the right walboro 255lph pump? I have having trouble finding the exact one that I need for my in-tank set up.

Thanks for all the help so far guys! I have learned a lot!

[RedHeartbeat]

Gss-340

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Gss-340

Thanks Red Heart!

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Gss-340

On that fuel pump what kind of modification would I have to do to make it fit?

[RedHeartbeat]

You can contact NelsonPerformance and they will send you the right pump and you'll be sure to get a genuine Walbro pump, not some knock off look alike pump. They can also answer any modification questions you may have about installation. There are a couple writeups on here about installing one. Do a little search and you should be able to find one.

[Sleaper]

Thats sounds like a good plan. Should I be able to safely run the stock injectors until I can get it tuned with the larger injectors?
So I am guessing that swapping eight injectors on this vehicle doesn't take much time?

Oh and can some one point me to the right walboro 255lph pump? I have having trouble finding the exact one that I need for my in-tank set up.

Thanks for all the help so far guys! I have learned a lot!

The injectors are pretty easy to swap out. I'm not sure about running it with stockers without a tune. Especially when you have new motor, heads and cam. Might not run right but someone else can chime in on this and provide a little more help.