Here are some pics of the new plugs (C65YC) with about 5 miles on them. And, for comparison, the old C59YC plugs with less than 30 miles on them. Someone please tell me what the hell is going on here. The 65's are supposed to be a lot hotter than the 59's. My carb float's are set good, I leaned up the A/F. The screw's are only 1.5 turns out. My car isn't getting over 160*, could this be because the heads (combustion chamber) aren't getting hot enough to burn the mixture? Do the 65's look like they are gonna foul in the next 50 miles









For reference, I found this pic on Edelbrock.com

 

Don't know what the equivalent heat range is for classic A/C's to a c65yc is, but I think you are rich.

1 1/2 is too much. I usually run at one turn out. Sometimes less. 1 1/2 is my starting point, and I lean out from there (warm engine).

With that cam 2 things come to mind:

1. What power valve is in there?. I'm thinking you need around a 6. Is it busted? Suck on the diaphram side and see if it holds vacuum. yummmm. Also make sure it has correct gasket. Perfectly round gasket goes on a power valve that has a step register for it. The gasket with internal spikes goes on pv with round drilled holes instead of windows.

2. Big cams can require more air so engine won't stall. Cranking on the idle speed screw results in exposing the tranfer slots too much, causing engine to run rich and have an off idle stumble. Common fix is to drill small holes in primary butterflies to feed it more air. that way you can back down idle stop so only about .020" of the slots is showing. I start at 1/16" hole in each butterfly. If idle speed is still too low, I drill up a little at a time. 1/8" max.

I like to start with the factory size jets in a 750 vacuum secondary. 71 front, 76 rear and go from there. I run 160*, and don't have fouling problems with A/C r44s, but I have iron heads. don't think it would be that big a difference if they were aluminum.

 

Oh yeah, look out for casting porosity too. Bottom line, if everything is correct, you should be able to crank in an idle feed screw and at less that 1/2 turn, engine should start to run rough. If you crank one in all the way, engine should die. If it doesn't, excess fuel is being introduced from a source other than the idle feed screw. the transfer slots, power valve (popped or opening too soon), or casting porosity.

Other common cause is float levels too high, but you said that is good. Be aware that on new installs it is common for dirt to get in a inlet needle at any time. wouldn't hurt to pull the sight plugs and check float levels again.

 

So, I will try 1 turn out and see how she goes. The PV does seem to hold vacuum, although if you try to suck on it too many time you get a buzz........gas.....whoa

 

What gap are you running? Are the plugs the correct reach for the heads? What kind of coil?

To get an accurate read on your mixture, you need to get a good light and look down into the base of the porecelin. Looking at the tips doesn't do much good.

 

first the only way to read plugs is give it a full throttle blast through the 1/4 then turn off the engine with no idle time and pull them