cant they make it anyway you want?
Yes, that's all you have to do, you can use your roller lifters again (tell the cam mfg. what you have).
This is the same thing that many 12 port head buyers 70 years ago had to do: when the valve positions don't match the original engine the cam is changed.
The next question: how to select the right grind (and intake and exhaust lobes may be different), complicated because of the supercharger. Falconer may have experience with boost on the V12... good place to start.
Although your cam can't be reground (not enough material in the lobes) it's worth money to another builder.
In his defense, Falconer may have asked you if you're aware of what's needed, and assumed "yes", and certainly didn't mean to mislead you or misrepresent the product.
You may find a magazine is interested in running a feature on this when it's done.
You're going to be the "go-to" on this!
