over heating issue

i swapped factory 305 to 350 trying to keep emission legal. the issue i have is the vehicle runs hot on high run meaning 55mph and on. car runs normal on low idle. i'm wondering if the computer can't handle the 350 needs or can i install a different chip, or should i just say the hell with the computer. this is on a 87 monte carlo ss. NOTE everything that water flows thru has been replaced

My suggestion is to remove al computer and emmission components, Changing the chip will make you have other problems, go with a carburated engine

Or do the easy thing and put in a lower temp thermostat :)