i don't know much about nitrous plugs but the timing looks perfect and the rest looks good also maybe a tad lean but not sure .do the specks on the porcelain look metallic or is it the pic ?
A little primer on nitrous plug reading. You're very, very close to where you need to be. Timing looks to be nearly perfect and just a hint more of fuel and you'll be right on it. Nitrous Plug Pictures and discussion - Dragstuff
N/a engine is 350 to 375 is my guess. 100 shot of n2o. Cam is Hughes solid 237 and 242 @.050 lift is .560 and .570 on a 107 Lisa in at 104. Stand alone fuel system for n2o with 110 race fuel. Flowing pressure is 9lbs. Not a nitrous cam but what is in the engine. Speed master heads with correct springs.