This is a common issue with all the trucks with fuel tanks like this. HotBodies, Savage, Gen's, and Nem's. The only way to omit the whole problem is to nip it early, as early as when you first break in the engine. If you tune the engine with only a half tank of fuel and get the temps to run fine there with a good smoke trail at around 260-280F then you should do fine even with a full tank. Only thing is you may need to go with a hotter plug to keep it running at the full tank. But give that a try. Tune your LSN and HSN with only a half tank in those temps. At a half with temps in 260 you will end up empty at 280. With a full tank it will seem a bit slugish but will get going after it warms up and should temp at about 220-230 full. I hope this works for you, the only other option is to go with the HB's style tank for the savage and mod it into your CEN to work like a buggy.