My propshaft height using a straight edge to the front of the nosecone on my bravo std lowers comes in at 4.5 inches below the running surface. I rarely have more than 2 people in the boat and minimal gear. Even when I tested 27p mirage 3 blades the boat came on plane fine without using tabs so I think we're ok in that respect. I'd like to get the bow up some more, but if we move to -2 shorties will it hurt or help this?

Our experience is if you can get on plane with 3 blades at 4.5" BTB you will be able to get on plane at -2.5" BTB but you likely/may have to go to the Bravo 1 props. If you hit the sweet spot/combination, it could give you +4-5 MPH. The worst case is you sell the -2 lowers and Bravo 1 props if you don't like the result. You could also likely borrow Bravo 1 props for testing. Keep us posted on your project.

I have bravo 28s and 30s and they bite better but the 4 blades drive the bow down. What effect does raising the prop shafts 2' have on stern lift?

Going to -2 shorties will give less bow lift with less leverage to lift it.
If anything, I would have the props labbed to reduce stern lift and increase bow lift.

Thanks Griff, I've been talking to BBlades but we need to test some more with the 30s before settling on a plan for a prop mod. If I do the shorties after the props we might end up with expensive paperweights so its a coin toss now. Anyone have 2 shorty lowers they can lend me?