Listed here are a set of replacement machined aluminum Velocity Stacks for the Fujimi Ferrari 641/2 kit in 1/20 scale.

They are made with the same outside diameter and height but with an altered lip contour and slightly larger bore completely through. Slight modification with a 3/32" (2.38mm) drill bit to the tray mounting bores are required for installation. Inside bore and lip have been polished. Tray and drill bit mentioned are NOT supplied.
Not sure what other kits they are similar to for other uses. 12 pieces supplied.