In case you didn't read my main thread on the project...
Yes, the special L67 parts were bolt-up to the LN3. No special fabrication. I visited Ryan of GMtuners/Sinister Performance and he did the tuning, and he said that performance should be close to what a stock Series 1 L67 at around 220 hp.
Most my posting was at the Reatta.net board, but I came here since I figured you LN3 guys would really be interested in this. Swapping the entire L67 in (I bought one) may have been better for long term durability but I'm not really worried about it. Hal/2seater at the Reatta board has a turbo LN3 pulling like 260-280 hp, so it can't be that bad on mine.
Lots of details on this project, but I'm happy with how it turned out.
I am planning on trying it out at a track sometime this summer. Not sure what older Bonnevilles weigh but my Reatta is around 3400 lbs, so you can compare performance. The parts are stock except for a cheap APC ricer cone filter. Can equally be done to an L27 too (Greg Ross on the Reatta board has done it).
'89 Buick Reatta. Formerly propelled by a supercharged LN3, soon to have Series II L67/ 6 speed manual http://<a href="http://www.bonnevill...sc&start=0</a>
'93 LeSabre Limited...$450 fixer upper my friend bought and is having me fix up though currently my driver for the time being