Trailblazer piston melting?

[mechanic]

I was hired to fix a 01 Trailblazer 250, the guy had no idea what was wrong with it. Turns out it was running lean and as a result melted the piston and rings. The piston had a hole forming on top of itself, the exhaust side of the rings were melted to the piston. I rebuilt it all and ran it at a moderate speed for 10 minutes, the spark plug was a perfect healthy brown. Did the same thing, had the same results. Should I go up a jet size just to be sure that it doesn't melt another piston, or should I chance it and say its good? Any input would be helpful. Thanks!

[blueline15]

Oil injection or premix?

[mechanic]

Oil Injection, but if that failed then the bottom end should have seized before the piston started melting?

[mechanic]

anybody else have any idea?

[SMP63]

Gotta feeling once E15 hits the pumps your gonna see more of that happening!