RE: Good Race ready drop in Engine for the Rusty
Any 3-port, .12 size engine. The rusty is a bit heavier than other st's so something with more go to it than a CV series engine might be on your list. OS CV-R is always a good choice, Fantom fr12 (I love mine), Orion Wasp .12 (rear exhaust port), nova rossi (not very affordable), RB concepts has nice engine. Tower will sell the OS and Orion engines.