Do you know if your heads have hardened valve seats installed? You could have a problem with seat recession with no lead gas. IIRC hardened seats weren’t used until ‘71. However a lead substitute additive should alleviate that.
I’ll let others chime in regarding their thoughts on ethanol...
And I wonder how many of these brackets are sitting in miscellaneous pails in auto wrecking yards the last 40 or 50 years long before anyone realized they’d have value. :confused:
Very valid point. I installed an electronic ignition that fits inside the factory distributor cap on my '74 back in 1990. So that's 16 years with points and 32 years with electronic ignition. :cool:
Pardon my "canned" HEI answer but the pole piece (AKA "pick up coil" in the distributor) causes problems like that. While it may be fuel related, eliminate ignition first.
That rod was missing when I got my '74. Having to shift into reverse to get the key out is a bit of PITA but I think the main reason its removed is because some makes of headers interfere. In any event, it also activates the back up lights and that's the biggest annoyance without that rod in...