SKU: 95781536554

MACE PERFORMANCE 6.35MM PLENUM SPACER TO SUIT FPV GT BA BF FG BOSS 290 315 5.4L V8

Sale price$72.86 Regular price$80.95
Save 10%

Pay in installments of $20.24 with ShopPay, AfterPay and Klarna

Shipping Estimate
USA
  • USA
  • CAN

Ships within 48 hours · Estimated delivery Aug 21 - Aug 26

Promo Codes Available:

For Your Every Summer RSVP, with Code: SUMMER15

Description

MACE PERFORMANCE 6.35MM PLENUM SPACER TO SUIT FPV GT BA BF FG BOSS 290 315 5.4L V8Exclusive to Mace Engineering is our design registered plenum spacer to suit FPV Boss 290 and 315 V8 engines. What is a plenum spacer and what does it do? A plenum spacer thermally separates the plenum cover and intake manifold. Its main purpose is to improve air distribution between cylinders by slowing down the air speed inside the plenum chamber. As a result there is less of a pressure drop inside the plenum chamber between cylinders, and less air

Exclusive to Mace Engineering is our design-registered plenum spacer to suit FPV Boss 290 and 315 V8 engines.

What is a plenum spacer and what does it do?

A plenum spacer thermally separates the plenum cover and intake manifold. Its main purpose is to improve air distribution between cylinders by slowing down the air speed inside the plenum chamber. As a result there is less of a pressure drop inside the plenum chamber between cylinders, and less air momentum, resulting in better air distribution and power. The change in airflow characteristics is shown in the diagram below.

Not only will our spacer help you make more power, it will also help prevent any costly rebuilds through dangerous lean outs that occur with standard manifolds in high horsepower/boost applications (due to poor air distribution).

In addition to improving air distribution between cylinders, the increase in plenum volume also has a positive effect on bottom end torque.

The fact these spacers are manufactured from the same thermal resistant composite material as our manifold insulators means further horsepower gains are possible due to the reduction in heat soak.

Key benefits:

  • Design registered.
  • Reduces charge air temperature resulting in better power consistency and detonation prevention.
  • Power increase with no undesirable side effects.
  • Improved air distribution between each cylinder.
  • Improved fuel economy.
  • Easy to install.
  • Can be used as a replacement gasket.
  • Reusable.
  • Proven gains at an affordable price.

Contents:

  • 01 XPlenum spacer
  • 01 X Silicone gasket maker
  • 04 X Spacer bush

Vehicle Fitment Guide

Note: Installation is very straight forward, requiring only the removal of your plenum cover to install the plenum spacer.

Shipping Notes
  • Free Standard Shipping on $100+ Orders to the USA.
  • Except Preorder products are shipped in 48 hours.
  • Delivery to the USA:
  1. Standard Shipping : 3-10 business days
  • If time is of the essence, please consider selecting expedited delivery for faster service.
Exchange/Return Notes
  • We offer a 30-day return/exchange service after receiving.
  • Final sale items are not eligible for returns or exchanges.
  • To process your return/exchange, please contact us at [email protected]
  • Please click here for more details>>> Return & Exchange Policy
SKU: 95781536554

Discover Niche Categories That Outsell

Top-Converting Item to Boost Your Average Order

4.2 ★★★★★
Based on 18 reviews
Sort
Highest Rating
Newest First
Oldest First
Product Reviews
S
Verified Purchase
S. Brown
Massapequa, US
★★★★★ 3
Very tight fit on 74mm Mobile 1 Filters
Color: Silver
It claims to fit "some" 74mm Mobil 1 filters. It's a fraction too small, but will work if you "force" the tool on the filter.
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on February 25, 2026
D
Verified Purchase
Dustin
Pawtucket, US
★★★★★ 5
Works if you need help. Not a miracle in a bottle.
Size: 1 Count (Pack of 1)
It has worked every time I've used this product. Won't fix a damage catalytic converter but will help you pass the test if your car almost passed.
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on May 28, 2026
L
Verified Purchase
Leslie Price
Carnegie, US
★★★★★ 5
Worked like a charm.
Size: 1 Count (Pack of 1)
Used it as directed. Down to an eighth of a tank. Poured it in and added enough gas to get back to one half a tank. Wanted to get it mixed in really well. Immediately jumped on the interstate and ran 75 MPH for 40 miles. Stopped and filled the tank and when I restarted the engine, the light was off. Coincidence? Not a chance. Light had been on continuously for weeks. AutoZone said I needed a catalytic converter. Nope. One thing I found out the hard way. If your gas filler has a flap at the top, make sure it is easy to push aside. Mine had a little release button near the top that the filler hose would depress before the flap would release. Dumped the first bottle right on the ground. Twelve bucks wasted. No one to blame but me, I guess. Still a bargain, even at twice the price.
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on February 17, 2026
B
Verified Purchase
Brenda A DeRouen
West Palm Beach, US
★★★★★ 1
Before use on March 15 two days later March 17 engine light still on
Size: 1 Count (Pack of 1), Size: 1 Count (Pack of 1)
I read the specs on this product and it was guaranteed to cleanse as well as turn engine light off in vehicle. I received it March 14.2026 and used it on March 15.2026 I took a picture on Sunday before I entered it into the gas tank engine light was on at that time. Today is March 17.2026 and engine light is still on. The truck was driven for one hour on the 15th 45 minutes on the 16th and 50 minutes on 17 March. Still the engine light is on. Got home parked the vehicle took a picture again to show engine light is still on product guaranteed it was shut it off, but unfortunately product does not work.
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on March 17, 2026
A
Verified Purchase
Amazon Customer
Lexington, US
★★★★★ 4
Good stuff
Size: 1 Count (Pack of 1)
I've used and it's worked for emissions for me and that's with having check engine light on..use stuff,drive around a bit,clear code drive to emissions and should b good unless got serious problems. It's good to use 1 or 2 times a yr if high mileage vehicle.
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on January 1, 2025

recommand products