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New AFR LS1/LS6 Head WOW!

Hib Halverson

Technical Writer for Internet & Print Media
Jan 10, 2001
CenCoast CA
71 04 12 19
Last week, I met with Tony Mamo, Manager of Product Design at Air Flow Research. The main subject of our meeting was the aluminum cylinder head AFR makes for big-blocks and the use of that on the "Big-Block from Hell", 71 Coupe project car (see http://www.idavette.net/hib/vette_bbfh.htm). In the process of discussing AFR's "Magnum BBC" head, Tony mentioned to me that AFR had just begun shipping its new LS1 head and our discussion immediately shifted to that significant news.

AFR is the first aftermarket cylinder head supplier to come to market with a serious high-performance street and mild-racing head for the Generation 3 Small-Block V8 engine family. Called the "Mongoose Street Head" (not to be confused with Corvette Concepts' use of the "Mongoose" name), the new AFR LS1 head incorporates significant, cutting-edge technology developed by Tony Mamo and the engineers at AFR. The combustion chamber is a modern design with double quench pad area which improves airflow. In addition, because the AFR Gen 3 head is not produced under the constraints a big company like General Motors puts on its production cylinder heads, the Mongoose's ports are designed with performance as the primary goal. Structural enhancements like AFR's trademark, 0.750-in thick head decks (a valuable feature for supercharged and nitrous injection applications), reinforced rocker stud bosses and thick-wall port runners provide excellent reliability/durability in street hi-po or racing duty-cycles.

The new AFR's intake port volume is 205 cc. While that's just a bit less than that of the LS6 head, the AFR's port design and, thus, its performance, is better than the production LS6 head. Numbers supplied by AFR indicate the intakes can flow up to 300 CFM at .600-in. valve lift which is about 70 CFM more than most stock LS1 ports can flow. The Mongoose Street Head comes with 2.02-in intake and 1.60-in. exhaust valves. The seats and faces are finished with three angles. This head has bronze valve guides and comes with valve springs (130 lbs seat pressure, max. lift of .550-in. Other springs are avail.) and titanium retainers. It has all stock accessory mountings. It can be had with either 66cc or 76cc combustion chambers. Both milling and angle milling are available. The standard Mongoose Street unit is CNC-ported and has CNC-machined chambers but is also available in a less-expensive, "as -cast" version for those on a budget.

AFR's LS1 head is a direct bolt-on. The head is intended for use on the 346 cuin. LS1 and LS6 engines in 97-04 Corvettes, 98-02 Camaros and Firebirds and 04 Pontiac GTOs, but it fits all Gen 3s and may an outstanding choice for the six-liter engines in pick-ups and SUVs. This new head will also be an excellent enhancment for the LS6 in the coming, Cadillac CTS-v and it's likely to bolt on to the six-liter, LS2 in the 2005, C6.

This head is brand new to the market and I have not seen any independent dyno testing or flow testing numbers, but Tony Mamo told me that these heads, when installed on an LS1 along with a street hi-po camshaft and FASTs new "LSX" composite intake manifold, can add about 100 horsepower, an astonishing increase which begins at about 2700 rpm and extends to the rev limit of the test, 6900 rpm. Complete dyno data is on AFR's web site. Even in the unlikely event of a worst-case scenario, ie: those numbers are optimistic by, say—20%; Air Flow Research's new cylinder head will have a major effect on the performance aftermarket for the Gen 3 engines and will offer a hell of a lot of bang for the buck.

My guess is AFR is going to sell a lot of these Mongoose Street heads. If that's not enough, an even higher performance AFR Gen 3 head, the "Mongoose Strip Head" with 225 cc ports, is in final development and Tony Mamo has a killer, all-out racing Gen 3 head with even larger port volume on the drawing board.

Want more info? Air Flow Research, 10490 Ilex Av., Pacoima CA 91331-3137 Ph: 818 890 0616 Web: www.airflowresearch.com


I wonder how this cylinder head compares with the cylinder heads that are built by tuners such as Lingenfelter.


Well-known member
Nov 28, 2001
Northern NJ
Good info ...Any word on final dyno testing of stage II ported heads vs. AFR ?

Not just peak but the whole rev band?

Same engine ...same cam...same headers...just differrent heads.

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