Peterbilt 300 Series Ultra Cab Unibilt 5.5" Extended Day Cab Conversion

After ordering you will be contacted with the freight cost.

Current lead time is 2 weeks.

Instructions

The Peterbilt 300 Series Ultra Cab Unibilt 5.5" Extended Day Cab Conversion Kit allows for the removal of a non-integral sleeper unit while adding 5.5 inches of extra legroom and seat recline over a standard factory layout.

Designed for models like the 357, 367, 377, 378, 379, 386, and 389, these kits are not interchangeable. When ordering, you must specify your exact cab setup CHECK YOUR MEASUREMENTS BEFORE ORDERING:

• Non-Unibilt

• Unibilt

• Ultracab

Each package comes complete with an extended fiberglass rear panel, rear window glass, sealing trim ring, full mounting hardware, and your choice of interior upholstery in Black, Tan, or Gray.

Pre-Assembled Air Ride Suspension Upgrade

To eliminate the difficulty of disassembling factory sleeper suspension parts—which are often frozen or damaged by rust, wear, and corrosion—an optional pre-assembled air ride suspension system is available:

• All-New Components: Built as a complete unit so you won't need to reuse any of your old, worn-out factory suspension pieces.

• Direct Frame-to-Cab Mount: Includes all necessary hardware to secure the assembly directly from the converted cab to the frame cross-member. (Note: Models such as the 386, 367, or 357 may require an additional riser plate due to cab floor variations). RISER PLATE

• Heavy-Duty Weatherproofing: Features fully powder-coated mounting brackets to ensure long-term corrosion resistance and maintain a clean appearance.