One thing I was unsure of when assembling the GX390 to the gearbox was there was a little gap between the engine and the gearbox. Not large but I noticed it. After reaching out to @marinegrunt , @MuscleMyHustle, and @Firefighter4hire all 3 confirmed it was normal. Just wanted to share for anyone else assembling a gear drive for the first time.
I used the larger bolts and spacers that came with the pump. I used copper anti seize on the shaft. I had a buddy help me assemble it and I held the key way down while sliding the gearbox on the shaft. As stated in another thread you can zip tie the key to the shaft, slide the gearbox partly on then snip the zip tie and remove it. My new GX390 arrived with a zip tie on the key on the shaft.
