UMI Performance · New
UMI Performance 65-66 GM B-Body Adjustable Upper Control/Trailing Arm
MPN 3657-B · Store SKU umi3657-B
Supplier stock checked 11/7/2026, 12:49:18 PM UTC. Adding a part does not reserve it.
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Product details
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. 3657 - 1965-1966 GM B-Body Adjustable Upper Control/Trailing Arm
Manufacturer fitment & guides
Check 3657-B against the manufacturer’s application information below.
Part-specific notes
- California Proposition 65: Y
