3.5 x 3/4 is about the right dimension for the gov spring. The linkage return spring p/n was changed from VT2434 to A29988 last p/n interchange I have.
I bought the spring at a hardware store. Just measure an approx length with some added tension. Doesn't have to be perfect, it just pulls the throttle rod back. Any tension that may affect the gov can be cancelled out by adjusting the gov spring.