Rather than using the acetal plastic .
I'd just replace the springs with new one's .
PIC
https://i.postimg.cc/bv1krjCW/SM-420-2nd-Gear-SPRINGS.jpgYou'll need ( 4 ) of the Pins / Rivets that secure the Springs
to the actual 2nd. Gear . These are pretty rare parts & are hard to find .
PIC
https://i.postimg.cc/cHZY85PH/2nd-Gear-Pins-Rivets.jpgDan's GM Obsolte
Chinook , Montana
phone : 406 - 357 - 2615
Dan's has ( 37 ) energizing springs
He also has ( 3 ) of the Pins / Rivets
Llewellyn GM Obsolete
Northridge , CA.
phone : 818 - 363 - 5094
Scott at Llewellyn
has ( 1 ) of the Pins / Rivets .
George
'54 3600