I have a 54 261 in my 46 and have a boiling over problem. The radiator is not pressurized since I used the original radiator (rebuilt) from the 46. On a hot day (in New Mexico that means 95 and up) when I drive up hill about an average of 20 degrees for about 2 miles and stop to turn on the road to my house the motor boils over. I can drive around town, idle, get on the Interstate and run about 60 MPH, all day. It only boils over when I make the last 2 miles on the up hill incline to my house. Haven't figured this one out yet. The temoperaturesare starting cool down so the boiling over will quite until next summer. Let me know what you findto be the solution?
