The research was carried out on the multi-operational drilling-milling-boring machine design with a six-spindle turret head. A 3D project of a multi-operational machine tool was proposed in the Creo Parametric computer-aided design system environment. Advanced CAD Creo “Inheritance” functionality was used to build three-dimensional models of cast housing parts, considering the casting process’s features. For parts with complex contours of mechanical transmissions of the machine drive and turret head, using the “Rounding” element in forming a multistage profile is considered. An innovative design of a V-belt drive transmission with a modified side profile is suggested. The research results of a transmission with a V-belt, the cross-section of which is a curved trapezoid. An analytical apparatus and methodology for determining the basic geometric parameters of a belt provided the curvilinear cross-section of a modified belt drive is equal to that of a standard trapezoidal profile, are proposed. An analysis of the belt height’s influence on the belt drive’s reliability characteristics was performed. An experimental calculation of the main geometric characteristics of the belt-modified version and comparison with similar characteristics of standard designs was conducted. Comparative analysis with standard V-belts showed potential transmission advantages in terms of belt durability and pressure on shafts and bearings without increasing the belt cross-sectional dimensions. A set of sections for a new type of V-belt similar to the current standard is offered.