Velocity Stacks

Velocity Stacks: the bellmouth that smooths air into your intake

A velocity stack is the flared trumpet that bolts to the mouth of a throttle body, carburetor, or intake neck. The radiused bellmouth lets air turn the corner into the runner without tearing away at the edge, so the incoming charge stays attached and moving cleanly. That is the whole job of velocity stacks: reduce the turbulence a sharp-edged opening creates and give the engine a tidier path to draw from. Builders fit them on individual-throttle-body setups, on carbs, and on custom intake tracts where a raw pipe end would otherwise be sucking air across a knife edge.

What ThreePiece stocks

This category currently holds 9 velocity stacks from 3 brands: Vibrant (5 in the range), BLOX Racing (3), and K&N Engineering (1). Current in-stock pricing runs from $56 to $165 - that is the live range for what is on the shelf, not a standing offer.

The Vibrant pieces are aluminum bellmouths listed by neck and bellmouth diameter, such as the 2.5in neck / 6in bellmouth stack and the larger 5in neck / 8.75in bellmouth stack. BLOX Racing brings composite stacks like the 2.5inch composite stack and the 4.0inch composite stack. At the top of the range sits the K&N Custom Velocity Stack Assembly, 11 in, in red.

How to choose

Choose by diameter first. Measure the neck outer diameter of your throttle body or intake pipe and match it - Vibrant lists both neck O.D. and bellmouth O.D., so you can confirm the stack seats where you need it and the bellmouth still clears surrounding hardware. Aluminum stacks like the Vibrant range give you a rigid, machined mouth; the BLOX Racing composite stacks come in at the lower end of the price spread and in tighter 2.5in and 4.0in sizes. The K&N assembly is a larger, complete unit at the top of the range for setups that want the bigger 11 in piece. If clearance is tight under the hood or against a bulkhead, pick the smallest bellmouth O.D. that still covers your neck size.

What else you need with it

A bare stack draws unfiltered air, so most builds pair it with filtration. Look at Replacement Air Filters, Panel Filters, Drop In Filters, and Air Filter Elements to keep debris out of the runner. If you are building a full induction path, the Cold Air Intake Kits and Cold Air Intakes categories cover complete systems, and forced-induction cars can add from the Intercoolers range. Browse everything under the parent Air Intakes section.

Fitment and ordering

These stacks are listed by size, not by vehicle, so confirm your neck diameter before buying. For help matching a stack to your setup, call 813-535-5801 or reach us through contact us. All orders ship free, and Affirm and Katapult financing is available at checkout.

Velocity Stacks: the bellmouth that smooths air into your intake

A velocity stack is the flared trumpet that bolts to the mouth of a throttle body, carburetor, or intake neck. The radiused bellmouth lets air turn the corner into the runner without tearing away at the edge, so the incoming charge stays attached and moving cleanly. That is the whole job of velocity stacks: reduce the turbulence a sharp-edged opening creates and give the engine a tidier path to draw from. Builders fit them on individual-throttle-body setups, on carbs, and on custom intake tracts where a raw pipe end would otherwise be sucking air across a knife edge.

What ThreePiece stocks

This category currently holds 9 velocity stacks from 3 brands: Vibrant (5 in the range), BLOX Racing (3), and K&N Engineering (1). Current in-stock pricing runs from $56 to $165 - that is the live range for what is on the shelf, not a standing offer.

The Vibrant pieces are aluminum bellmouths listed by neck and bellmouth diameter, such as the 2.5in neck / 6in bellmouth stack and the larger 5in neck / 8.75in bellmouth stack. BLOX Racing brings composite stacks like the 2.5inch composite stack and the 4.0inch composite stack. At the top of the range sits the K&N Custom Velocity Stack Assembly, 11 in, in red.

How to choose

Choose by diameter first. Measure the neck outer diameter of your throttle body or intake pipe and match it - Vibrant lists both neck O.D. and bellmouth O.D., so you can confirm the stack seats where you need it and the bellmouth still clears surrounding hardware. Aluminum stacks like the Vibrant range give you a rigid, machined mouth; the BLOX Racing composite stacks come in at the lower end of the price spread and in tighter 2.5in and 4.0in sizes. The K&N assembly is a larger, complete unit at the top of the range for setups that want the bigger 11 in piece. If clearance is tight under the hood or against a bulkhead, pick the smallest bellmouth O.D. that still covers your neck size.

What else you need with it

A bare stack draws unfiltered air, so most builds pair it with filtration. Look at Replacement Air Filters, Panel Filters, Drop In Filters, and Air Filter Elements to keep debris out of the runner. If you are building a full induction path, the Cold Air Intake Kits and Cold Air Intakes categories cover complete systems, and forced-induction cars can add from the Intercoolers range. Browse everything under the parent Air Intakes section.

Fitment and ordering

These stacks are listed by size, not by vehicle, so confirm your neck diameter before buying. For help matching a stack to your setup, call 813-535-5801 or reach us through contact us. All orders ship free, and Affirm and Katapult financing is available at checkout.