I have a 66 Valiant (amarican dart), 400 with stock heads,M1 single plane intake, 2 1/4" with 4" collectors fender well headers, 4" flowmasters, .528-284 mech cam, MSD 7al2 ignition. Had a wilder 383 before but too much for the street. My problem is that once it gets hot it won't cool down. I...