Posted by Kaegi [98.247.164.246] on Wednesday, November 05, 2014 at 00:45:12 :
In Reply to: Hardened valve seats? posted by J-Gilly [68.9.113.210] on Tuesday, November 04, 2014 at 22:04:23 :
all mopar flatheads from about 33 till the end of production had hardened exhaust seats. the HD versions also had sodium filled valves as well. lead additives are not needed either way but they cant hurt and might extend life a little. The reason they have harcened seats is because before WW2 gas was 50 to 70 octane and most did not have any lead in it. quality high octane leaded fuel in the auto industry was a post WW2 development.