I have some Ford green-tops (42#) I need to get rid of at some point.
I agree changing pressure AFTER tuning would cause a complete retune to be necessary. But if he goes from NA to boost, he will have to completely retune the car anyways, so I wouldn't be concerned with tuning the NA combo on 39 psi and turning up to 50-55 base when and if a moderate level of boost is added.Running high pressure is a bandaid and forces you to change the whole tune once you hit the wall with a smaller injector. 80's will run fine on the street and are good to about 1000hp boosted with gasoline.
Lets face it.. A lousy 350-375hp is not enough. We are in the golden age on BOOST. Get your long block together and go for it..
My method of thinking is: if you’re buying new, all good injectors are going to cost over $300. Why not just get a set of 80s, they’re basically the same price as 47s. Been there, done that. Never buying a new injector again that’s under a deka 80.Seems a little ridiculous to go straight to a deka 80 for what you are doing. Best thing to do is get an injector with published data for the sake of tuning. For your needs, I would go straight to Ford Racing's line of injectors... Published data. Affordable price. Consistent quality. Few "fakes" floating around. Readily available.
A favorite of mine is the LU47. On low fuel pressure it will do quite well for your n/a fox application. If you add a blower down the road, you can turn up the pressure and these can take you quite far on pump gas. As an example, my 2017 coyote car has those injectors on it with a roush blower. It runs at around 60-65 psi, and is supporting over 600 rear wheel horsepower on that setup.