I have a 57 with a big block and its running hot, I'm wondering if exhaust size mite be an issue. so here is what I have, original 68 Corvette high performance block and heads, headers, with 21/2 inch pipes off the collectors, was thinking of going to 3 inch pipes. its also got a new griffin rad. electric water pump and fans, 180 thermostat. Any input would be appreciated.