Flex fuel injectors

[ghettoluxury]

I am at the point where I am getting ready to start working my harness and wanted your input. I have a complete 5.3/4l60 that I pulled from a 99 Silverado. I am putting it into my 73 step side for a nice daily driver that is decent on gas. I also have a 2004 5.3 flex fuel engine that I bought for parts.

So here lies my problem, I was looking up flow rates and noticed that the injectors on the 99 are only 21.8 lbs. The flow rate for the flex fuel injectors is 33 lbs but the connections are different. So now I have to decide what injectors to use prior to building my harness. I know that the flex fuel injectors will help if I do power adders, but will it hurt my fuel economy until I decide to go that route. The guy flashing my pcm said that he needs to know what injectors I am using as well.

I guess the question I am trying to ask is will the 33 lb injectors vastly effect my fuel economy on a stock tune?