FWIW - In April, I swapped from truck nozzle rebuilt injectors set to ~ 2200 psi to marine nozzles set to 2250 (also from Barry). It felt like there might have been a small, noticeable power increase, but nothing remotely as dramatic as the +40 hp or more some vendors claim.
Barry checked pop pressure & pattern on my old injectors - the patterns were fine. 7 popped around 2200 & one at 2000. The engine now runs a bit smoother & would suppose the lower popping injector could explain this.
I do think there is slightly more fuel flowing at WOT at rpms above 2500 as there was a small but again notable decrease in WOT fuel pressure (read just before the inj pump). Something on the order of maybe 1/2 psi lower. Tough to really correlate that to a quantifiable volume of increased fueling. Just thought I'd mention it as this is at least a bit more objective that "feels like it makes a bit more power."
So far I've put about 25k miles on my engine since building it & have diligently recorded all fuel fills/mileage since. I've put around 3500 miles on since the swap to marine nozzle injectors - going to/from work w/ pretty consistent route/speed etc. There appears to be a small improvement in fuel economy compared to the same timeframe the previous two years - possibly around 0.5 mpg. It's gonna take more mileage before I'd say this fuel economy bump is real but 'ya can't complain about a positive trend.
So far, my opinion is that paying a significant premium for marine injectors wouldn't be a great value. That said, if you can get marine nozzles for similar cost & you have a pump that's fueling a little more than stock, there might well be a small benefit.
