Based on the octane rating, I would initially agree that over 14:1 would be pushing it. But after talking to the guys over at raceone85.com, they know of one car that has been running 6 or 7 years on a drag car with 14.7:1 compression and they have had no issues with detonation. Another car they knew of was a huge BBC motor that had 15.2:1 and ran pump E85. I understand that E85 doesn't have a real high octane rating but it really seems to resist detonation beyond what one would think it could handle. I also talked to a guy at engine connection who designed this motor in my car for the previous owner. I asked him about the fuel it needed. He said probably 112 to 114 minimum. I also asked about running E85 and he said that the car would run it. I said "even in a 15:1 motor?". He replied "yes, but tune the car for it and you'll be fine." So after talking to these people who know way more about this stuff than I do, I am very hopeful that this conversion will indeed work. Just my2 cents.