I was told the turbo injectors would allow too much fuel and will lower the fuel economy and cause even more smoke(if that is possible) How was the performance of it after the swap? That was one of my options was the 6.5 turbo marine injectors with the 4 spray holes
The injectors can't flow more fuel. The amount of fuel in each pulse is controlled by the injection pump, and the injectors will flow as much as the injection pump sends it- no more, no less.
Where they differ is that the nozzles and pop pressure will be engineered to match the flow rate of the pump they were made to be matched with. A 6.5 injector is engineered to be optimal with the flow rate a 6.5 pump provides.
So if you put injectors engineered for the high fuel rate of a marine 6.5 turbo engine on a NA 6.2 with a stock IP, you will be pushing the same amount of fuel through a larger orifice. You are likely to get less than optimal fuel atomization like that, and worse performance. Worse fuel atomization means a less complete burn, and more smoke with less power and economy.
All those "40hp Marine Injectors" are nothing but snake oil.