Posted by Kaegi [76.22.23.236] on Monday, November 09, 2015 at 22:15:42 :
In Reply to: M37CDN, 251s, and Unleaded Gas posted by Greg Coffin [67.176.56.44] on Monday, November 09, 2015 at 21:26:10 :
all mopar flatheads went to hardened seats in 1933 or 1934. run unleaded without issue. I have never had to replace one in many rebuilds. there are 2 types of hardened seat but even the regular ones seem to hold up really well.