engine still not cool enough

I had this problem when I brought my car.(70 340 swinger) stock. It had a aluminum rad with ele. Fans. It ran about 210 deg. With that setup. I like stock look so I pulled the rad and fans and put in a stock rad. With a clutch fan and shroud,ran even hotter 220 deg. Changed t-stats. Also ran with no t- stat still hot. Water wetter still hot. Had the rad recored.(3core) still hot. Got a good deal on another motor(340) rebuilt solid cam,porter,polished heads 0 miles.installed the engine and it also ran hot. I still had stock exhaust manifolds and exhaust system all the way back.
I put in TTI headers and exhaust system (2 1/2 inch) now it runs 180 190 all day. GO FIGURE.