USA Standard Gear

ZP Spool Differential for AMC Model 20

$427.57

SKU: ZP FSM20-3-29

In Stock
In Stock
Ships by Aug 31
Free Shipping over $200
$100 Minimum Order
30 Days Return

Description

The USA Standard Gear ZP FSM20-3-29 is a robust steel spool designed as a performance upgrade for AMC Model 20 differentials. This component ensures that 100% of available traction is delivered to both wheels simultaneously, regardless of surface conditions. Engineered with 29 spline axles and intended for use with 3.08 and numerically higher gear ratios, this spool is a direct fit for the AMC Model 20 axle housing. While offering maximum traction, it is important to note that this type of differential is not recommended for street-driven vehicles due to its aggressive traction characteristics. It is best suited for off-road applications, drag racing, or other performance-oriented uses where maximum grip is paramount.

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.

Fitment

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Specifications

BrandUSA Standard Gear
Part NumberZP FSM20-3-29
CategoryDrivetrain

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Returns & Fitment

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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Shipping

Orders are processed in 1–3 business days. In stock parts ship promptly from our partner network. Special-order items either aren’t currently stocked or are built to your spec — expect 4–6 weeks. If a part goes on backorder while your order is in the queue, we’ll reach out and work through discounted alternatives together.

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