I run them with the washer. I checked the depth on the threads before assembly, and these housings could run them without. I wouldn't run them without the washer unless you had the engine open and verified the depth of the thread.

Side fire. The plugs are the exact same length as the stock plugs, when modified. Prior to modification, they're a bunch longer. They won't fit unmodified. Unless you want a new motor, don't try. Really. Imagine a 50 thou gap and another 70 thou of ground strap trying to fill that 30 thou opening. Plus, even if it looks like it might fit, remember that metal tends to grow and move around at high temps...

Non Resistor NGK racing plugs, if I remember correct. Might want to check the NGK catalog if resistor is a big deal to you, I'm kinda fuzzy on why the part # starts with "R".