New Suntour 8.8.8. Multiple Free Wheel 5 Speed 126.96.36.199.34. for 1/2 x 3/32
This is what I would use. High Quality.
You may be able to rebuild this freewheel and get larger than 34 teeth.
You may need to space the frame wider and add spacers. This has been done before on OCC's and may be documented.
Bicycle Scooter Sprocket Metal Wheel 3 Speed Freewheel
Made in China. I would replace balls with grade 25 and pack with grease.
You may not have spacing issues. You may be able to rebuild this freewheel and get more teeth.
This might work:
Home built disc brake on motorized Schwinn Stingray