https://www.hpiracing.com/ can be a valuable resource and that engine has long been discontinued.
1411 is the part # that you want - piston / cylinder / conrod / wrist pin / clips - already assembled.
1410 is the part number for just the piston and cylinder.
Unfortunately, these parts have been discontinued too, but you may be able to find them somewhere like eBay or even possibly here.
You want to replace the conrod along with the piston & cylinder = so just get everything.
Connecting rods take a beating.
If you go to the HPI site and search for the part number that I gave you (1411), you may find there's a replacement part that is currently available somewhere.
You can, and they are about a hundred bucks.
While you have the engine apart, changing the front and rear bearings at this time is advisable, especially if the engine has been run a lot.
But to do so, you'll find out you'll need a bearing tool kit that you probably don't have.
So, between the piston / cylinder etc, the bearings, and tools you'll find that you may be ahead of the game in both dollars spent and avoided aggravation by just going out and buying a new engine.
There are multiple engine options available for $150.00+/-.
