[asphaltgambler]

I'll chime is because there is significant reason to replace the pistons and rings at this stage. The whole idea of leaving well enough alone is a good one except in this case. Stock Harley pistons and rings are designed for quite operation and good ring seal for the mass market. Unfortunately this does not lend it self well to a high(er) performance engine. The stock pistons and rings create a lot of frictional drag in the bore.

When you increase cam lift, spring pressure and RPM's on that EVO cylinder/head "sandwich" the cylinders tend to "lift" with heat, piston/ring drag. Ask me how I know.

On an engine of that size the frictional loss of horsepower is a lot more than you would think with the stock pistons/rings. Buy a good set of aftermarket performance pistons (short skirts) that accommodate narrow and less tensioned rings. Keith Black as well as others make a good street performance low-drag piston/ring combo that still provides reasonable noise limits as well as good sealing characteristics. Last I checked the price point was very moderate.

Also keep in mind that you may want to bump (slightly) the static compression ratio when replacing the pistons as I believe the stock is something like 8.5:1 to 9:1. You will see huge improvement by going up a full point in static compression.

Lastly, since the rings and pistons are already out of the bore you have 'lost' the rings locations within the cylinders. So you now must hone and replace at least the rings.

Final note too...................you should check the assembled deck height with base gasket, new pistons (only) installed and then use two of the stud nuts and torque them to 30 Ft lbs. Measure your deck height. You should shoot for something close to "0" as the head gaskets are very thick. There are several companies that sell varying thickness cylinder base gaskets. If you cannot find one thin enough you should have the bottom of the cylinders machined. Any good machine shop can do this.