Yeah the O.S is definitely one of the best nitro engines. And it's a drop in which makes it even better. All the power of Big Block in a small block foot print.👍👍
I just posted a thread from the traxxas forum about the jato and what's needed bud
To be honest your best easiest option. Would be throw the O.S .21 in the jato.. has the displacement of a big block. But without the big block.
You would also need to figure out where to throw weight on the front end of the jato.. I got this for you off the traxxas forum...👍👍
https://forums.traxxas.com/discussion/526763/big-block-jato-how-to-guide-w-video
Well it will definitely be alot faster and more tourqe then the 3.3 that's in it. Have you done any upgrades to your trans with the gears? And drive train?