Dan,
The bore in my sump measures 2.255 diameter.
Mark,
Though my upgrade to the SDS EFI seems like a great time to move to the new sump configuration, I am interested in documenting the performance directly attributed to the EFI. I was able to chart the performance benefits from dual magnetos to the single SDS CPI, and then once again when I went dual CPI, so I think I have a pretty good handle on an ignition scheme optimized for my mission profile. I am hoping to take the same tack with the fuel side. Once I get that as far as practical then I can change the sump, optimize, document and compare. Follow on changes will be playing with induction and header tube length to see if I can find any hidden performance there. These kinds of changes would be really time consuming and expensive to accomodate with the mechanical fuel injection, but the SDS system will change with a few keystrokes.
All that said (and my reason for posting in this thread), the 80mm SDS TB on the stock updraft sump is unlikely to provide any benefits vs a RSA-5 sized version, but the big TB certainly wont hurt anything and is still shorter than the RSA-5 by quite a bit. It should easily fit in a stock RV-10 cowl.