Those are all good questions. The only limit on modifications are your time and budget. You didn't mention which class your going for at Bonneville as that might dictate some of the mods.
To list just a few potential engine mods...
Re-angle and or shape intake ports
...The list goes on
I want to lighten the flywheel , do you know what grams can be taken off ? Or a size pattern I can machine off ?
We usually run the bringwhatyoubrung , I have raced in the 500cc vintage class .
As for time , I figure within 6 months .
Do you know if I use the dyna III electronic ignition if that would accommodate dual plugs ? I can check on that …
Compression ratio for pistons ?
Can you share a link for the Roller cams ?
I was gonna reshape the intake ports , any insights?
I truly appreciate you and your input . Thank you
As for a roller cam, well that's a totally custom thing, you'll need to see if you can get someone to grind you a cam. Then you need to source the lifters, old HD were used. Crane did the old race bike cams, but I am not sure if they would be able to help these days. I'm guessing you could count the number of roller cam engines built on one hand, maybe two hands. One of them is in my profile pic, a few in museum at factory. Another guy named Rudy has one in Germany that he rides a lot.
There are plenty of electronic ignition available that work with the dual plugs, dynatek, EnDuraLast, Boyer, etc.
There is no magic answer for compression. Its all going to depend on what your goals are, what kind of fuel you want to burn and 50 other parameters....etc.
As for port shape, again, not something we can hand you a cad drawing and say go do this. If your gonna re-angle the carbs to be out you have a lot of welding work. What size valves will also dictate port shape. Having a flow bench will help. If your sticking with a stock head then maybe just clean up the rough spots with your porting tool and move on.
Maybe best approach is build a mildly tuned engine and make tweaks from there as you learn what works. Look at it this way, if you went to a local Friday night car show and asked every chevy owner there how to build a kick ass motor, everyone of them will give you a different answer. Only difference with the BMWs are there are fewer folks around these days.
You are right , the variables are numerous , so many elements and yes build up and fine tune as we go . Elevation , gas , materials , oil flow etc . I have built a few very special engines with fantastic results and have over built with catastrophic results . The Gnosis is half the fun in this realm , thanks for the reminder .
I will continue and update as I go along