novacain, the best plan is to work toward a balanced dragster. Yes engine location is important with a balanced race car, measure from the motorplate, ie back of engine to the center of the rear axle. Our JrFuel car is 48" with a 225" wheelbase, and a total of 325 lbs of front axle weight, and car total weight , with an all iron 406 ci SBC, and with driver is 1435 lbs.
Your car with the 355 sounds close to a good balance, but with more power you may need to add at least 25 lbs of ballast to start with.
You can't win races or have good runs if you can't steer the race car. We run 7.0's with a 5 foot long wheelie bar about 3" off the track. My 2015 plan is to keep adding more ballast and keep raising the wheelie bar to the point where we don't hit the bar, but still only get the front wheels up 6". Keep-in-mind you will need more ballast than us because your car is short at 166" and you weigh 100 lbs more than our driver. So your 260 lbs is behind the axle there-by having more of a chance of pulling the front up. i have given a few FED the suggestion to add 20-25 lbs to the front only to have them run faster. Also your slicks might be too big and they "dead hook" and not spin enough to keep the engine RPM in the right HP range.
Another thing to keep-in-mind is a too tight converter can yank the front end up at the hit. i have had racers call Hayden Wheels asking for a front wire wheel light disk because they are red-lighting too much, but what they really needed was a looser converter so at the hit the wheels would not come straight up out of the lights.
I don't know of any "ballast formula" because there is so much that can affect car balance, engine location, HP, torque, wheel base, converter, launch RPM, slicks, tire pressure, wheel width, tire speed, weight of the front end and rear weight too. Try something on every run until you get a well balanced combination.
Jon Hansen, Hayden Wheels, 800-624-3803