By now you’ve probably heard of a small Californian company called Air Flow Research — or AFR as the kids are calling them these days. But what you may not know is that their famed line of Mongoose heads has grown by one and now includes offerings for the rectangle (or square) port worshipers out there.
If you are familiar with the Mongoose line of heads, you know that they are typically one of AFR’s higher end options and are known to move a lot of air. Typically they are still reasonable for street driving duties but typically have more in common with a max effort pair than with a mild CNC’d set.
“Our Mongoose line in the past was just our LS1, LS2, LS6—anything cathedral port, whereas these new heads are rectangle port and are built specifically for the LS3,” said Chris Sperling, director of engineering and technology at AFR. “They will fit anything with a 4.00-inch bore or larger and use the four or sixth bolt mounting pattern, depending on which set you go with.”
And with flow numbers like these there is a lot to be excited about. These monsters are flowing 384 cfm at .700-inch lift on the intake side of things and 255 cfm at the same lift on the exhaust. To put that into perspective, the exhaust on these bad boys is flowing as much, if not more, than a set of LS1 castings.
Flow numbers like these are typically reserved for all out racing heads with canted and modified valve angles. These, however, retain all of their stock valve geometry that GM intended and thus don’t require special rockers or other valvetrain pieces.
The pair utilizes a 260cc intake runner combined with the stock-sized 69cc combustion chamber. The intake valve measures in at 2.165 inches while the exhaust is a reasonable 1.600-inch unit, both of which are stainless steel in construction. The valves also come with Titanium retainers and PAC dual valve springs.
The heads are cast from A356 aluminum and then CNC’d to perfection. And, if you live in California like we do, you’ll be pleased to hear that these bad boys carry a CARB number as well. So, if you’re sick of getting beat by snakes, maybe you should think about picking up a pair of these Mongoose…es…Mongeese?