Hard to believe it's vapor lock on a 70 F day. Mine only vapor locked once, it was 115 F in Blythe and overheating from other problems. Could be a number of things. A fan shroud helps in traffic. I removed the plastic vent connection (and shoved a shop rag in the vent) at the 3" diameter hole in the radiator support at the left side to get more cool air to the carbs. You could do that on both sides, but engine bay heat might not be the problem.

I just checked the resistance on the coil and found it was .8 across the primary and 4.3 across the secondary. The specs list .355 and 4.4 so the primary resistance seems to be a lot higher than it should be.

I don't know if that would get worse when it gets hot or not.

I know the pertronix wants 3 ohms for resistance but since the MSD 6a is actually triggering the coil that shouldn't affect the pertronix... right?

I've thought about removing the MSD 6a as it seems like overkill for a stock street car and it is actually quite loud mounted on the kick panel. I guess if I do that then I'd need to switch to a regular 3 ohm coil.

Edited March 30, 201312 yr by ta240