The 8 cc tanks and a dual port cyl will run 3.5 to 5 min depending on nitro, prop, needle setting. That is more than enough for starting, tuning, and 10+ laps. A tad bit rich so you don't go overlean and have a flame-out, and you should still be good for 15-25 laps.

Just googled Bell YFM-1 images, there is a pic of the same model, with Cox .049s, and what appear to be 8cc tanks on it.