Line/injector Size
 

I'm looking to flow enough fuel for about 400 hp n/a and 600 hp on the bottle.

I have a worked over lm7 that i think can make that much, and I have read some conflicting stuff on fuel line size and also injectors.

I have 36lb (at 58 psi) injectors, a walbro 450 in tank pump, and the 99-02 return style fuel rail. This all seems like more than enough to flow the 400 hp right?

The lines I have coming from the tank to the rail are 5/16. At 60 psi, will this be enough to support motor and spray?

Line size is PLENTY big. If you are doing a dry shot you probably want some larger injectors, with a wet shot 36lb are right at the limit for 400hp. I would look for some 40-45lb ones for a wet shot or 50-55lb for a dry shot.

Thanks for such the quick reply atomic! I'm glad 5/16 will be enough, that will make my project much easier.

5/16 is smaller than -6 correct? -6 means 6/16 or 3/8 right? why do most people recommend -8 for most fuel line setups?

Will the 450 overpower the regulator at the rail? or should it be ok? I've read that it will overpower the corvette filter/regulater combo and I don't want that tuning hassle.

I would get an aftermarket regulator and a set of billet rails off ebay for your intake. They will look much better than the factory ones and aren't that expensive. You will have issues with the 450 and the stock regulator.

Tubing and hose are measured differently, AN hose is measured by the Inner Diameter and tubing is measured by the Outer Diameter. -6an hose has the same ID as a 3/8" OD tube. The difference being the tube generally has a smaller thinner wall. Most guys say -8 because that will cover you up to 1500hp and its not much more money than a -6 system. -6 is slightly larger than 5/16, but not appreciably. You have plenty of pump to make 1000rwhp on the 5/16" lines NA if you want to.

Awesome! Good to hear fuel won't be the reason this blows up. Upping the pills to beat the guy in the next lane probably will.

Will the stock regulator not be able to bleed off enough fuel at idle and run more pressure than it's supposed to? I'd like to keep the stock rails if possible so is there a good solution to keep stock rails and fix the over-fueling at idle?

I think some guys have drilled it out but not sure how well that works.

Would a 340 be a better option. Should support 700 hp and won't overpower the regulator quite as bad as a 450 right?

I would do a walbro400 then if you really dont want to upgrade your regulator.