New to nitrous

[John_Heard]

That's a lot safer than where you were at without a doubt. Your plugs will tell you if it's happy or not.

As mentioned earlier, locking the distributor out will make it a lot easier to read the total timing the engine is seeing. If you have a MSD distributor I believe most of those can be locked out easily.

[find01]

The distributer is a Mallory unilite. It does not appear to have an external mechanical advance of any sort. The shaft can be twisted, like it has spring tension against it and that must be how it advances at higher RPM. As far as the plugs I have read and re-read your arcticles on how to properly read them, but it is still confusing to me. The strap on the autolite plugs are very short. Do I still look for the heat mark to be at the bend or would it read higher on the plug? Before I melted the strap off of the #4 cylinder last weekend the prior reading showed the base of the plug was between 40% - 50% clean/overheated. Also can you see the black specs from detonation with the naked eye?

[John_Heard]

Yes, you're looking for that mark on the strap to be away from the plug base and at the bend. The closer it is to the electrode, the less heat is in it. Just imagine heating the electrode up with a torch till the tip is red. When it cools there will be a heat line on it. If there is no line, it probably wasn't hot enough to put one in it.

This actually sounds like an interesting thing to do in the garage one of these evenings just for fun on a new plug to show the difference in temps...

Not sure what you mean by "40/50% clean overheated".

Black specs are not hard to see, looks like pepper on the white porcelain. There is a number of opinions on what those are from. Some folks say ignore them, some say it's oil that got past the rings and caused detenation, others say it's from the coating on the plug burning off. The specs that look like itty bitty pieces of aluminum, those there are no doubt a bad deal. You might have seen some of that on those ones that burnt the tip off.

[find01]

What I was talking about when I said that the base was 40-50% clean was the base of the plug body, looking directly from the bottom, looked to be clean to both sides of the ground strap, with the strap approximately in the middle of this area. Where across from the ground strap, you could see dark brown to slightly black left from the run. The porcelin was white. I mistook this for running lean, which it turned out to be too much timing and too hot of a plug. It probably was burning the fuel off of the plug base and this was my heat ring?? I had been looking at the porcelin with a 2.5X magnifing light and could just barely see tiny black specs. That's why detonation wasn't crossing my mind.

[71Hellride]

The porcelin is what you want to look at. The very bottom is wide open, where your at on nitrous. I also like to run ngk plugs. The groung strap is weaker than the autolite. I don't know much about your distributor but i'm sure it can be locked out. MSD's have the springs you can change to change the advance curve, but you can take it apart and flip it around and it will lock the timing. It's very easy. If you don't feel like doing it then go with what you got. Sometimes you just need to try one thing at a time, I know I do haha. As far as your timing numbers my old small block only liked 36* on the motor. It never hurts to take a couple more degrees out just to be safe, even more so if you get your tune up extremly clean. The tune up John gave should work real well. Hope it works out for you buddy.