When I fired up my current engine for the very first time, it was so rich it was literly washing the cylinders down!!!!
I was getting blue and black smoke pouring out the exhust. Shit I went almost threw 1 gallon of gas in 20 mins. I thought I trashed the rings and bearings. But luckly I didn't. After changing the air bleeds and Idle feed restrictors it was all good!
By the way.....my headers never glowed.
Another thing is when you start to run bigger cams, the plugs will always look fouled out when ran at idle for a period of time, untill you put a load on the engine. I am not sure how big "Z-303" cam is, (don't really care about the a,b,c cams anymore) but it's another consideration to think about when looking at the plugs when it has never been driven yet. (I assume). When looking at the plugs, you need to check them after you put a load on them....not at idle. We are not at the "stock relm" of tune-up any more. These are modified street/strip cars, and pure race cars. Two completly different animals. Another reason why the plugs might be black is, no compression due to various reasons, leaky injector, etc. Lets all back up some and do some basic tests first. Then we can all see how off I am.
I ran a 306 w/ 10.3 to 1 compression, t/w heads and a 232/242 @.050 cam and a modified, ported shortened Cobra intake w/ 30 pound injectors and it ran lean! I also had the Car-Tech Stage II fuel system on the car running 42 psi with a Speed Brain computer. (what a piece of shit computer
) I had to alter the stock fuel curve (add) to get it to run right. Another reason why I decided to just say the hell with it all and go carb.to save some $$