Everything I find on the net states that my Backdraft 3.5 should have an SH 21 engine in it, BUT right on the side of mine is "O.S. 21". So, I have two questions........

#1 - Did Redcat change from an SH 21 to the OS 21, or are the posts that I'm finding on the internet wrong?.... if Yes, then why if anyone knows?

#2 - What is the difference between the SH and OS engines, and which is "better"?

I'm starting to find that a lot of changes have been made to the Backdraft over the years, which is most likely a good thing. I'm happy overall with the buggy. The only drawback is getting parts after you break something, which I knew going in but didn't think I'd need parts so fast after engine break in, lol. So far I chewed a spur gear up while tuning it after a rock got caught between the pinion and spur gears. Now I'm waiting on a servo saver as I smacked a curb yesterday and broke the passenger side saver. I've learned my lesson..... no more running it with the body off unless I'm driving just to tune it, AND no more crazy driving in the street!

Thanks in advance for the responses gang!