Small Block Down Flow Radiator

I have a radiator post in the big block section about a summit rad we used in the yellow duster the upper is on the pass side but its a 27x19 2core alum summit rad for a fox body stang and I had tabs welded to it I made but it cools the 440 in it fine with no probs. We took it out a cpl nights ago when it was nice and hammered it a bit to see if it stayed cool and it was fine cooling a 10-1 440 w/stage 6 heads and the 528 mp solid, prf rpm, has a 3500 stall and 3.91s. has a 440 source water pump and no thermostat(has a restrictor).