Pro-M GM-855L: GM 85mm 5 Pin Mass Air Meter


Pro-M GM-855L - Pro-M GM 85mm 5 Pin Mass Air Meter. Pro-M mass air meters for GM applications appear to be exactly the same product that you have seen advertised by other manufactures. All aftermarket manufactures (Pro-M included) start with the same production GM meter. The entire housing is machined, allowing it to flow more air than the stock meter. This is where the similarities end. Modifying the meter housing allows the meter to flow more air, but in the process, the calibration of the meter is thrown way off. Other manufacturers simply ship them with the calibration off. This is because they lack the capability to correct it. The competition’s meters will require that the vehicle's computer be chip tuned to compensate for the mis-calibrated meter. Every Pro-M meter is calibrated to match the original meter's calibration. These meters can simply be installed in place of your original meter, with no modification to the computer, allowing instant results, with none of the hassles associated with aftermarket computer tuning.


  • 01-07 Corvette
  • 01-03 Olds Aurora V8
  • 2005 Bonneville
  • 05-06 GTO
  • 04-05 Cadillac Fleetwood
  • 00-05 Cadillac Deville, Seville, Eldorado
  • 99-00 Full-Size Truck - (with 5 pin MAF)Includes Tahoe, Yukon, Suburban, Full-Size Van, Commercial Chassis
  • 01-06 Full-Size TruckIncludes Avalanche, Tahoe, Yukon, Suburban, Full-Size Van, Commercial Chassis
  • 03-06 Hummer H2

Product Summary

Pro-M GM-855L: Mass Airflow Sensor for Chevrolet Corvette 1994-2000
Manufactured by: Pro-M
Model: GM-855L
Product ID: 18679
Price: $329.00
Condition: New

About Pro-M

History and information about Pro-M and their products.

Pro-M Racing was founded in 1989 by Bob Atwood, a Ford engineer who was instrumental in pioneering mass air technology. Pro-M quickly became the most respected name in the industry, offering the only real practical solution to the restrictive production mass air meters found in most of today's production vehicles. We manufacture mass air meters in various sizes, shapes, and styles, as both direct bolt-in replacements, and in universal designs, to maximize your engine's horsepower potential, by allowing your engine to breathe to its fullest potential. Each mass air meter is individually calibrated on one of our in-house flow benches specific to your particular application, and fuel injector size, eliminating the need for time consuming and expensive dyno tuning. Others make claims, but only Pro-M Racing possesses both the intellectual and physical properties necessary to calibrate your mass air meter to within two percent of what the OEM considers the perfect baseline. (In comparison, OEM meters are typically held to within 6 percent). Quite simply, despite their claims, no other company even knows what this baseline is. For those who choose to have their vehicle professionally tuned, all of our meters are supplied with a flow data sheet. The flow data sheet provides extremely accurate and invaluable information for tuners, greatly reducing the time needed to properly tune your vehicle. All of our mass air meters can be installed in a matter of minutes, and will provide immediate results.

In case you didn’t know, the Mass Air Flow Sensor in your car has a very important job to do and that is it sends your car’s engine a signal with measurements that aid in the calculation of fuel delivery and spark timing – hard to believe isn’t it. It is able to accomplish this by means of an electrically charged wire that can tell how much air is entering the air intake and then in turn it creates an electrical voltage, transmits it to your car’s phenomenal computer system and as a consequence the spark timing is adjusted as well as fuel delivery and spark advance. If you find your car’s engine stalling, rough when it is at idle or you are using much more gas then you used to then you could have a faulty Mass Air Flow Sensor, or if you have added aftermarket performance parts to your car these may have resulted in additional air flow and your car’s factory Mass Air Flow Sensor may not be accurate creating problems in performance and fuel economy. If it is time to replace your car’s hot wire type sensor from the factory with an aftermarket high performance mass air meter consider the ones designed and manufactured by PRO M RACING, the company that has the performance engine in mind when they go to the drawing board. Innovations like the Pro-M 92mm Universal High Flow Mass Air Meter V8 on the LMPERFORMANCE web site with its bell mouth design and non- protruding sampling element and its 360 degree sampling design, a truly a remarkable piece of engineering and it is available in any calibration so it has wide spread use. Also from PRO M RACING and available at LMPERFORMANCE for your Cobra, Mustang or Ford Truck the flanged air meter with its billet aluminum fabrication, welded construction and anodization it will outperform and outlast any competitive product and be much more eye appealing, a very important attribute if you are showing your car. Peruse these and all of the other outstanding PRO M RACING meters on the LMPERFORMANCE web site and get your upgrade at a competitive price.

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