slow speed is hard to keep a big block cool that slow at car shows .i would like to see the big blocks i have had run it 160 but they run around 210-220 on very hot days and had one that would get to 240 but that was a 14.8 548 cid it just ran hot but i never hurt it was built loose for very hard running .i always look at the oil psi if that was not dropping i would cool it down