Rad Problems

Hey Guys i need some input on a problem I'm having!! I have a 1935 Ford that I'm running a 460 Big Block Motor in I had brand new tanks made from the originals and had a new core installed at a very reputable rad shop( they actually do all the rads for Big Cat equipment) well I have recently just started doing some highway driving with it and I took it on a 20 mile run it ran at around 180 the whole time brought it home and parked it in the garage later on i noticed a serious leak coming from the rad..I seems the stock plates on these tall rads arent strong enough for the core expansion and was causing the core to bulge and come apart I took the rad out and back to the rad shop they fixed all the leaks and strapped the side plates side to side front and back I threw in a 160 thermostate for safe measure and replaced the clutch fan with a really good fan that moves alota air..So this past saturday I took the car to a show and shine 60 miles 1 way it ran at 160 on the highway and peakled at 180 idriving threw the city when I got to the show I parked it and noticed a leak running from the top of the core straight down and dripping off the lower tank..shit. So before i left the show to come home I checked the fluid and it was good!!! Same thing all the way home ran a beautiful 160 highway 180 in the city I noticed a little spray on the windshield and figured yah it's still leaking..when I got home I parked it in the driveway cracked a beer and watched it for an hour NOT A DROP LEAKED FROM THE RAD!! so tonight i just took it for a spin around town temp never got over 160 ran around for about an hour came home parked in the garage I just went out to the garage and it's dripping steady down the core off the bottom tank it's not the overflow line I'm positive!! so I am just frikking baffled!! why didn;t it leak after I got home from a 60 mile hard run??? I can see a tube maybe leaking now... but why?? what's causing these leaks?? any input would be awesome it's driving me nutzzzz...

 

BTTT for this guy,,just because its cool that,,,




A)he's running a 460 in a 35 ford
and B) for only running 160-180 degrees

 

My radiator in the Willys has large tanks and will not take the pressure of an 18 pound cap without a seam leaking. I went to a 14 pound cap and the problem is gone.