My £0.01
Autolinea cases as Sparkywig and Karlos said, better not use them as there are too many issues with quality control and they require a considerable amount of time to make them work well. They are heavier, engine will run hotter as well, so unless i am building a horse power monster like a turbo 350bhp and above, i always prefer a new mag case.
Crank- if 69mm is what you want, go with a welded stock like DPR or a Scat 4340. Next best is 4340 CB. You might be fine with Empi or SSP as long as they mic properly. I found Empi to have a smaller diameter on the crank gear section, resulting in a not so tight gear to crank clearance more than once, so i prefer not to Use them anymore. The SSP is the same as the CB but without the same quality control; inspected properly and with measurements right they can be used. Always balance the rotating assembly as they are miles off.
I would go with a stroker as suggested if you buying a new crank, like a 78mm to make it a 2007cc’s.
B’s and P’s- i have been using AA’s with zero issues. They always are within less than 0.5g and perform really well unless you want to go turbo. The Mahle forged are great but i have to buy two or three sets to mix and match and get the weight to a balanceable state. They come sometimes within 10g which is impossible to balance without seriously compromising the strength of the pistons.
Heads- i have stopped using Auto Linea as the quality of the alloy is like cheese, try to machine and you will know what i mean. I now use AA 500’s, they have a modern combustion chamber heart shaped and also long reach spark plugs. Also the alloy is very decent
40x35.5 is too big imho for the 1776cc. You will loose port velocity at low rpm and therefore torque down low. The same AA’s 35.5x32 properly ported will make the same power on above combo without sacrificing the low end, i guarantee that!
Cam- the 110 is a well known good performer, on the 1776 for a Bus i am 50/50 but if you are the kind of driver that likes revving more, than i would say do it. If you drive mostly between 2-3.5k rpm’s i would choose another cam. Dual twin choke carbs will exploit the potential of the 110 if chosen, like 36 Dell’s or 40 IDF’s.
Gearbox- the 1303 will fit a Splitty not a Bay without heavy mods. Gearing is too tall, you want your engine turning around 3.3-3.5k rpm’s at cruising speeds for best cooling or else you will need an external cooler. My suggestion is a stock 002 box with 4.57 final ratio. John Walklett can build you a great box for cheap
Abel