I recall reading threads on here briefly mentioning the past use of the OPS 40, I'm pretty sure with a tuned pipe. I don't seem to recall much detail about the engines used, hence my question. Is the engine below, which I have (model 40 SLA RCA, fairly mildly timed, often described as for general "sport use" ) one of the ones that were used ? I'm guessing probably not as my hunch is that the rear exhaust engines were used ( which also may have been higher timed ? ) Mainly asking out of interest and I probably won't consider it's use in a c/l model unless it's particularly suited.