Below is a general manufacturer product group description. Please note the information below is not item specific. Item specifics are above in product details.

The engineers at Skunk2 Racing have worked tirelessly to develop the next generation of high performance intake manifolds and are proud to announce the release of the much anticipated Ultra Series Intake Manifold. Years of R&D have culminated in a multi-piece cast aluminum intake manifold that offers advantages that only a modular design could allow.
Building upon the performance legacy of our Pro Series Intake Manifold, as well as using the latest in CFD (Computational Fluid Dynamics) software; Skunk2 Racing has created a three-piece modular design that allows for easy disassembly, porting, and plenum volume changes through the use of a removable plenum and optional plenum spacers. In addition to CFD testing, the Ultra Series Intake Manifold has undergone extensive in-house dyno and on-car testing which has led to a design that is less restrictive, yielding both torque and power gains well over many of the competitors.
Ultra Series Intake Manifolds are made from high-grade 356 aluminum alloy for a strong and lightweight design, CNC-machined for a precise fit, and individually inspected for quality assurance. The large 90mm throttle body opening, 87mm velocity stacks, and hi-velocity intake runners with smooth transitions allow the Ultra Series Manifold to outflow the competition. Designed to be used with built, high-horsepower naturally aspirated or forced induction setups, the Skunk2 Ultra Series Intake Manifold helps provide a new level affordable high-end intake technology to the marketplace.
FEATURES:

Available in 3.5L, 4.5L, and 5.5L Configurations
Optional Billet Aluminum Plenum Spacers in 1L or 2L Sizes
Hi-Grade Mounting Hardware
6.5” Tilted & Tapered Hi-Velocity Runners
Raised 87mm Velocity Stacks – Plenty of Material to Port
Provisions for Additional Injectors on Bottom Side of Runners
Unique Mounting Flange Universally Fits All B Series VTEC Heads
90mm Throttle Body Flange – Std. 5.0L Ford Pattern
4 × 1/8” NPT, 3 × 1/4” NPT and 1 x OEM AIT Port
Includes Thermal Manifold Flange Gasket
Generously Cast Runner Walls for Porting
Fits ALL Popular Chassis Configurations – Not Just Race Cars