Runs like crap now

Yes, I suppose it’s possible. I thought I was being careful reinstalling but I want to pull them anyway to see if one or more are fouled so I’ll regap them at that time. 

I set the timing curve separately last fall before the carb swap. I had it up to 3000 rpm to check all-in timing and it seemed to run fine then, but it wasn’t under load. 

I do use Arctic Silver on the heat sink of the ignition module so that ought to be fine. 

in regard to the “crossfire cap” from the first reply… is that maybe referring to inductive crossfire? I hadn’t thought of that, but I’ll check plug wires 5 & 7 and make sure they’re separated. I’m using Taylor Spiro Pro wires. I’d think they would not be prone to induction but I’ll make sure those two are separated. 

Yes, The Taylor wires are worth the extra money and work well..

I’m resurrecting my old thread because I finally found the culprit. Yes, it’s been six months… lots of home improvement projects had to happen before I got back to working on the car. The wife is appreciative.

Turns out it was a bad plug wire all along. Plug #8 was oil fouled but I couldn’t see why at first. Seems the wire was close but not touching the header. That baked the silicone outer cover until it was hard and crumbly. I think the compromised wire was arcing against the header or block, but I never saw that because the view of that plug is blocked by the AC housing. I also never watched it run in the dark. I was effectively driving on  just 7 cylinders all this time.

I think I’m going to try the Accel ceramic boot plug wires. I can’t see any silicone boot surviving long near the headers. 

Steve

MOST EXCELLENT...!!!  Good sleuthing and congrats on figuring out the problem.  Now go drive it like you stole it...!!!