Holley 558-103 LS2/3/7+ (58x/4x) Engine Main Harness

Yes. Wholesale pricing is available for legitimate businesses that provide a valid business number or equivalent proof. Ongoing purchase volume is required to maintain discount eligibility. One-time personal buyers aren’t eligible.

If a product page clearly lists fitment for your vehicle and the description leaves no reasonable doubt, we’ll cover the cost of return if it doesn’t fit. Exclusions apply if prior modifications cause the issue. When browsing self-serve, you’re responsible for confirming compatibility by checking manufacturer fitment data and notes. If unsure, contact us before ordering and we’ll verify it for you.

We help where possible on a case-by-case basis. Most manufacturers include detailed instructions and tech support contacts. Because our catalog spans hundreds of brands, we can’t provide every torque spec or procedure, but we’ll connect you with the manufacturer if needed.

We don’t guarantee price matching, but we’re happy to review a legitimate in-stock offer from another Canadian retailer. The comparison must include all costs such as product price, shipping, taxes, and fees, and the item must be identical and available for immediate purchase. We won’t lose money to match unsustainable or out-of-stock pricing.

Yes. In-store exchanges happen on the spot when stock is available. For shipped orders, the original item must be returned first. Once received and inspected, we can issue a store credit toward the correct part or replacement. We can’t send a second item while the first is still in your possession without payment for both.

All prices on the site are before tax. GST, HST, or PST is calculated at checkout based on your shipping address..