Apologies for not jumping in for awhile, I'm in the process of moving this week.
Re the 350F - the carb spacing is tighter then the 500/550, so the filter is too wide for the bike. I originally checked this out on my 76 400SS. It would require a completely different kit.
Re the stacks for CR's / RS34's. I have already supplied just a filter (no stacks/ undrilled), so that is not an issue. However, given the cost outlay, I not prepared to change any of the current dimensions. So as long as they can fit within the existing filter effectively, I am willing to supply the filter/back plate assembly.
So as to not confuse people as to what is currently available, let's keep the CR/RS stack discussion in its own thread.