Quote Originally Posted by brute4c View Post
There was a member with the same problem many years ago...what he found eventually was that the leaf spring like tensioner arm on the points set was in the wrong place and wasnt providing the correct tension on the points...basically it was on tghe wrong side of the mounting bracket and that was enough to keep the pressure down enough that as the load got higher, the points werent keeping up.

In the following image, it is the flat metal plate that runs from the points past the arrow of #3 to the mount bolt that is in the line to the #4 arrow....hopefully that is clear...
Interesting. Thats the kind of experience I love about forums, thank you.

I've been into the ignition and rebuilt it all, so the probability of the spring being setup incorrectly is pretty high. I'll know for sure when I get the Pertronix points eliminator in.

Nailhead: my thinking is that the spring not applying enough tension would contribute to a weak spark, which the engine would run ok with no load, add significant load and the engine wont run as well on the weak spark. Add higher RPM and I'd bet the spring would "float" like valve springs if there was inadequate tension.

Parts should be in today, I'll let you know how it goes.