Buku small block models can be configured for all nitro motors from .12 up to .209 (TRX 3.3 and O.S. .21 TM) in displacement. For larger motors, see the big block pipes. ò 1 Fully Assembled Buku Power Exhaust System ò Header Coupling ò 3 Tension Springs ò High Power Convergent Cone ò Tuning Plug ò Adjustment Wrench ò Mounting Wire