Do I wait for the 5 speed?
I also have the GFI 855, a VERY early (March 2014, 3rd A-Body) unit that definingly needed some love from GFI, the original and still the manufacture of these units. All the bugs have been worked out of the newer units. Mine went back to GFI to address the issues, was corrected and turned within the month of February. I've had it up and running again and have autocross'd it three times this season starting March 30th. The updated unit no longer leaks, nor does it pop out of any gear and is quieter than before. Remember, this is a bolt-in old school transmission so it will always be louder than a modern TREMEC. It is also built on an 18-spline main shaft will will hold horsepower. As far as gearing goes, I run a 26" 285/35-18 with a B-Body 8 3/4" 742 3.73 with a rebuilt Mopar Sure-grip. Around town I'm usually in 4th gear, on the freeway, 5th at 2500RPM gets me to 74MPH and I still have the 2.64 first gear to get me rolling without beating my clutch. I'm now very happy with it thanks to GFI! Call John Huff and see what the timing looks like. I can't speak for other people, I can just share my experience.
already autocross'd with it three times starting
I also have the GFI 855, a VERY early (March 2014, 3rd A-Body) unit that definingly needed some love from GFI, the original and still the manufacture of these units. All the bugs have been worked out of the newer units. Mine went back to GFI to address the issues, was corrected and turned within the month of February. I've had it up and running again and have autocross'd it three times this season starting March 30th. The updated unit no longer leaks, nor does it pop out of any gear and is quieter than before. Remember, this is a bolt-in old school transmission so it will always be louder than a modern TREMEC. It is also built on an 18-spline main shaft will will hold horsepower. As far as gearing goes, I run a 26" 285/35-18 with a B-Body 8 3/4" 742 3.73 with a rebuilt Mopar Sure-grip. Around town I'm usually in 4th gear, on the freeway, 5th at 2500RPM gets me to 74MPH and I still have the 2.64 first gear to get me rolling without beating my clutch. I'm now very happy with it thanks to GFI! Call John Huff and see what the timing looks like. I can't speak for other people, I can just share my experience.
already autocross'd with it three times starting