Personally I think it is not cheap to buy an engine, even if it is a standard one, and especially one that has little other use. That and STD engine is not going to help your Locust much. If not get the STD175 or better yet STD180 you get from your raven/bj/TDK/etc. It is a bit slower, but cheaper. I would suggest throwing in a XL180 on i if you have one. And maybe even buying a XL180 which might be useful in the long run.
Wait... what else uses an XL180? Edit: Looks like other Locusts commonly use the XL180 (same weight as the XL175), since it is the most weight-efficient engine the Locust has. Also, some commando builds seem to work with an XL180.
