57 w/'65 327, +.060, about 10K(16 yrs) on this rebuild. I could not get it to timing right so I pulled front end off to verify timing. No problem detected, so painted, cleaned, flushed the cooling sys before removing radiator(rad new 4 core when engine was redone). Water pump showed signs of leaking so replaced w/similar hi flo pump. New thermostat, new hoses, all shrouds in place. No cooling problems previously. All back together, cools fine idling. When I went up the road, temp spike to 245, dropped back down to about 195, OK for a 1/2 mile, spiked again. Top hose was collapsing but replaced w/ spring loaded type, bottom OK. Still spikes but both hoses OK. The only think I can think of is the pump, but it is a good one from Chevy performance.