431.6 on stock internals.

[Steve]

Well if the injectors were at 100% at 500hp, then yes, but they were at 90% which means they are being stretched by 25%, as if the stock injectors were at 90% they would only be flowing 333cc.

[Sydneykid]

Hi R31Nismoid, there is one thing missing that I always include. You have to allow for some extra fuel for cold start, run and acceleration enrichment. The rule of thumb is 20%.

So the calc should be

HP = (520 / 5) * 80% = 83 hp Per Injector

That (520 cc's) is 40% more than the 370 cc standard injectors would deliver at standard pressure.

Hope that adds to the thread