I was reading through the shop manuals that I just purchased and it indicates push start in neutral and then push number one for low gear. I see now that the shop and parts manuals will be very handy.
Yeah, I meant to edit that after posting at work last nite, rear band needs to apply in manual low.
As far as performance converters for early 904's, the smaller input shaft and hub make it harder to find by far & the input obviously limits torque capacity compared to the later one.