1955-57 Tri-5 Chevy SBC/BBC Engine Side Motor/Trans Mount Kit

1955-57 Chevy Engine Mount and Transmission Crossmember Kit

On your 1955-57 Chevy car, the front motor mounts are at the front of the block and the rear mount attaches to the bellhousing. This works fine for original use but makes it hard to swap in a different trannsmission or add belt driven accessories to the front of the engine.

1955-57 Chevy Tri-5 Transmission Crossmember, Bolt-In, Steel

• Compatible with most modern automatic and manual transmissions
• Fits 1955-1957 “tri five” Chevy model frames, not for use with truck frames
• No welding required, bolts to frame once mounting holes are located and drilled
• 1-3/4-inch round bare steel tubing with .108-inch wall thickness
• 1/4-inch thick laser cut and press bent frame brackets
• 3/16-inch thick crossmember end plates and transmission mounting pad
• Includes hardware to mount crossmember brackets to frame and crossmember to brackets
• Fits TH350, TH400, 700R4, 4L60E, and 4L80E automatic transmissions
• Fits Saginaw 3/4-speed, Muncie 4-speed, and aftermarket Tremec manual transmissions

A Bolt-In Transmission Crossmember Conversion for Your Tri Five Chevy

Chevrolet’s iconic 1955, 1956, and 1957 models, affectionately referred to by enthusiasts as a “tri-5 Chevy” or “tri five Chevy,” are one of the most recognizable classic cars on the planet. From usage in dozens of movies and TV shows over the decades to magazine project cars like the famed Project X (which itself was also a movie car at one time), their body lines and classic styling work well for everything from straight axle gassers to pro touring builds and everything in between. Thankfully, we offer thousands of parts to keep your tri five Chevy running and on the road no matter the build theme.

The original engine and transmission fitted to the tri five Chevy had what some would refer to as “reverse motor mounts” with two mounts straddling the side of the transmission bellhousing area and one mount at the front of the engine. When performing a later small block or big block Chevy engine swap it is usually a good idea to upgrade from the standard single front mount to the later side mount configuration, which allows easier accessory drive fitment, but you need to add a traditional transmission crossmember to your ’55-’57 Chevy’s frame to complete the driveline support.

Tubular Steel Transmission Crossmember Supports Auto and Manual Transmissions

Our ’55-’57 Chevy transmission crossmember is specifically designed to support all the popular transmission options capable of being bolted up to a small or big block Chevy engine. Crafted from 1-3/4-inch round tubing with .108-inch wall thickness and CNC bent for precise transmission location, heavy duty 3/16-inch thick end plates are welded on along with a 3/16-inch thick transmission mount pad. 1/4-inch thick frame brackets are included to accommodate allow for bolting the crossmember in. The frame brackets are position on the upper inside edge of the frame rails and used as templates for drilling the mounting holes required into the inner frame wall. Mounting hardware for the crossmember and frame brackets is included as well.

Installation Couldn’t Be Easier with Basic Hand Tools Found in Any Garage

Our bolt-in tri five transmission crossmember frame brackets sit atop your ’55-’57 Chevy’s frame and are secured via self-tapping bolts once you drill the mounting holes. Then our crossmember bolts to these frame brackets. The crossmember is setup for standard two bolt GM transmission mounts. We offer both a standard rubber mount, as well as a urethane mount option.

Designed for popular GM automatic and manual transmission applications, including popular overdrive models, your options run from the old school tried and true TH350 to one of GM’s electronically controlled overdrive automatics. If you prefer your tri five with three pedals our ’55-’57 Chevy transmission crossmember will support all the modern Tremec aftermarket 5-speed and 6-speed variants, as well as classic manuals like the Muncie 4-speed and others. Note that the Tremec manual transmissions may require a spacer for proper driveline angle correction.

Chevy Rubber Motor Mounts, 4.3L V6/ Small Block/ Big Block V8

These 3-bolt S/B Chevy rubber motor mounts are manufactured to meet or exceed OEM specifications. Fits most 1958-73 Chevy passenger cars with small block V8. Sold as a pair.

• Unique rubber formula provides good abrasion resistance and aging stability
• Ensures maximum life and performance
• Application-specific Durometer (hardness) based on engine weight & torque
• Special Chemlock® bonding agent ensures superior rubber-to-metal bond
• These Chevy motor mounts fit small and big block Chevy engines as well as 4.3L V6 engines
• Unique rubber formula provides good abrasion resistance and aging stability
• Special Chemlock bonding agent ensures superior rubber-to-metal bond

1958-1982 GM Transmission Rubber Mount Cushion

OEM-style rubber transmission cushion for many '58-'82 GM transmissions including TH350 auto, Muncie, Saginaw, and others.

• Meets or exceeds OEM specifications 
• Rubber formulation provides abrasion resistance and aging stability
• Tough, hardened steel plate & inserts
• Chemlock® bonding agent ensures superior rubber-to-metal bond

Transmission Crossmember Instructions (PDF)

Engine Block Side Mount Instructions (PDF)

Transmission Crossmember Instructions (PDF)

Engine Block Side Mount Instructions (PDF)

• 6" total drop from top of frame and 2 1/2" drop from top of frame to crossmember mounting mounting tab