I used a set of 370's for years and I made my biggest numbers on the dyno using them. I had them honed out to about 70 liters a minute and that made all the difference in the world. My only suggestion is make sure you have the air to support the extra fuel. Dont worry about the washers I would make sure that you use the thinnest washer to get the spray pattern down in the bowl of the piston or at least close to it. When I took my original head off I saw the spray pattern on the bottom of my head. I didnt have the tip down far enough. They do haze at idle, but they are very streetable. Well thats just my 2 cents, but I am no diesel mechanic.
Stomp