IO-390 with lower compression?

Is it feasible / possible to have a Lycoming IO-390 built with a lower compression than the standard 8.9:1 ratio? So it might be possible to burn Avgas 91 or 93, or even Mogas non-ethynol.

Edit add 3/13/17 >> Informed by Lycoming Thunderbolt that they can supply an IO-390 that will "run about 200 hp and would be able to run on 93 AKI fuel" they do not recommend octanes lower than 93_AKI.

"1946 Bellanca Cruisair 14-13-2 (70 YRS OLD 8/15/16)
RV14A (N14ZT), Ser#140195"

Wouldn't it be wonderful if your Bellanca was still flying when N14ZT turns 70!!!

390 compression

Jeff, Lycon built me a 390 with .010 oversize bore and 8.7 to 1 a few years ago. First flight was July 2016 and now have 105 hrs. one it. They have their own forged pistons for .010 over. Runs great on pump gas and rings are finally seating. Also (2) P-mags with timing set at 20 degrees for now. Engine is not in a RV. Ron