RE: Top Flite Staggerwing
The ST 2000 is a .120, the 2300 is a 23cc, 2500 is a 1.50, 3000 is a 1.8, 3250 is 1.98. Difference isn't head gap, 2K and 2500 same motor, different bore and cylinder, a 2500 is in a 2K case, a 2500 is identified by a 2.5 stamped on the side of the left mounting ear of the case where the engine bolts to the mount if using a beam mount. Carbs vary by age of engine. A 7D OS carb works good on them as does an OS "F" plug and 10/10 fuel....