first, good luck on finding and acquiring a 930.
a few years ago with the prices of 930s going through the roof, thought I'd never be able to afford one. have had a poster of a 930 on my wall for YEARS.
well stumbled on a 78 SC/930 conversion not running. overall looked like a solid car that needed a lot of work, and just could not resist at the price the guy was willing to take.
about 6 yrs now into the FULL restoration and further upgrades to this car. I sold my 85 911 last year after 27 yrs of owning, in part for $$ to keep at the build of this 930.
car came with a modified 3.3 motor and a 915 gearbox. guy did not upgrade suspension or brakes so suspect never went to a track. sold the 915 to a friend and when he rebuilt it said was surprised it had not blown up. badly burned gears and parts from too much HP/TQ.
so I knew I needed a 930, 4sp gearbox. found a 930 4 sp gearbox that had been rebuild and shortened, needed for the SC tub.
like you I had read a lot of threads about 915/930, 4sp/5sp, etc. etc. if I had found a 930 gearbox needing rebuild/shortening, would have considered some gear changes. at this point will go with the stock gears.
hoping I live long enough to get this done .....
__________________
Bob Cox
78 930 clone project car.
87 924S resurrect at some point.
84 928S, Ruby Red linen/brown interior - sold
86 944 turbo my new DE/track car - sold