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Suspension and Components› Rear Suspension Components
UMI PERFORMANCE
UMI Performance 65-66 GM B-Body Adjustable Upper Control/Trailing Arm
SKU: U01C 3657-B
Moderate — 2–4 hours
Overview
Constructed with TIG welded mild steel tubing, it features greaseable polyurethane bushings and a durable powder coat finish. The arm includes a 4140 heat-treated CrMo adjuster for on-car adjustability and is compatible with both 3-link and 4-link rear suspension setups.
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Part #: 3657-B
UMI Performance offers one of the only on-car adjustable control arms for the rear of the GM B-Body vehicle. This rear upper control arm for the 65-66 GM B-Body is an excellent solution when looking to replace the worn out factory set-up. Our rear upper control arms are a direct replacement for the factory arms and are designed to minimize wheel hop, improve cornering and help track consistency. This control arm is on-car adjustable and allows easy pinion angle adjustments. Adjustments are made while the control arm stays attached to the vehicle. Competitor designs require you to remove the control arm from the vehicle to adjust. Adjustment can also be used to eliminate the use of shims during installation. Adjusting the control arm is as easy as loosening two jam nuts and turning 4140 Heat Treated Chrome-Moly Adjuster that utilizes left and right hand threads.
UMI's on-car adjustable rear control arm for GM B-Body replaces factory arms to cut wheel hop and sharpen cornering. Features greaseable bushings, TIG-welded strength, and a 4140 Chromoly adjuster. Fits 3-link or 4-link setups.
This product may expose you to chemicals known to the State of California to cause cancer, birth defects, or other reproductive harm.
Product descriptions are provided by our supplier partners and may not always be perfectly accurate. Not sure this fits? or call (760) 282-4645 and we’ll verify before you order.
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Specifications
| Brand | UMI PERFORMANCE |
| Part Number | U01C 3657-B |
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Built for enthusiasts. Every order is backed by our 30 day return window on eligible items. Unused and uninstalled products may be returned with approved RMA and no restocking fees when received in new condition. Orders placed through the MOTORMIA app with a complete build qualify for our Fitment Guarantee — free return shipping if the part doesn’t fit your exact setup. The guarantee covers fit only; installation must follow manufacturer instructions, and we recommend a qualified shop for parts marked Difficulty 4–5.
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