I am wondering if you guys could help me with a few questions i have? I have an 84 Royale with airbox lid with holes drilled and carbs rejetted, i didn't do the work. I can only get about 35 MPG, would like to get more. I have a bag with factory needles, washers and some of factory size jets. Cannot find in factory service manual number of washers or thickness needs to be under the needle, anybody help? Have not taken carbs off to see what size everything is, would like to only do this once. Are the factory size jets and needle the best way to go? Have seen in previous forums about shim under needle? I have a stock airbox lid with no holes i can use. Any suggestions will be helpful.