Harry,
Some tips on shaft alignment & angle:
1 Leave the stock 15º shaft angle alone...
2 Remove the struts & remove any wedges or pads between the strut & hull
3 Decide if you want to change the strut angle slightly outboard to allow shafts to be removed without dropping rudders. (
Relocation of Struts)
4 Re-install struts, without any wedges or pads. (Dry fit only at this point, but tighten them down fully.)
5 Align the engines & shafts to the struts, not vise versa.
While you have the struts down, that's the perfect time to deal with new inside backing plates as described in the Tips Section (
Classic Bertram Strut Problem)
You'll also be upgrading to 1 1/2" shafts which will be a very close fit through the bronze shaft alleys, so it would also be a good time to re-configure to the fiberglass shaft tubes. (
Building Fiberglass Shaft Logs)
And, while you're at it.... Keep in mind that your new air boxes will consume some of your height requirement necessary for an outboard mounted generator, so build in the new shelf to be absolutely as low to the hull bottom as possible.
And you thought it was just going to be a matter of swapping blocks... ;^))
Br,
Patrick