#7 connecting rod turned a straw color after cam r

Once built a 401 drove fine untill u turned it above 4500 rpm.
Turned it 6500 rpm in first hit second, again to 6500 . Hit 3rd
abou 5500 rpm started tighten up. Pushed clutch in, coasted to aarking lot
It died. Tried to restart, would not turn over.
Walked to mc Donald's and ate, went back to car it started fine and I drove it home.
Tom it apart, 2 straw colored rods at the crank end, took block to Mach shop, bad line bore.
Had it line honed and all was fine.
Ps the crank was polished afterwards, that's all it took, damn hard crank!!!

Thanks for all the replies and #6 looked fine along with #8, again the crank and the rod bearing showed no signs of overheating nor wear, the piston head was fine with no signs of damage and the rings were just fine as I stated earlier it was extremely lean as all exhaust valves showed signs of that but all plugs looked the same. It just seemed a little weird that only 1 rod would show signs of getting hot.