Independent Test Proves AFR
Out-performs The Competition

Chevy High Performance Magazine (CHP) Tested Every Significant Street & Race Cylinder Head On The Market

"Horsepower is where it's at, baby. And the best place to find it is with good cylinder heads." That's how CHP started their article Flow to Go in the 1998 CHP Small-Block Power special section; and we agree completely! The article continues, "A great way to evaluate a cylinder head is to measure how much air you can push through it." We also agree that flow test results are one of the most important factors in deciding which cylinder head will be right for your particular engine combination. And, nobody outflows AFR's CNC ported aluminum cylinder heads.

Independent Tests Tell You More

Most aftermarket cylinder head manufacturers publish flow numbers for their heads; but those numbers are not always comparable. These numbers may vary due to non-standard test pressures, inaccurate calibration, or creative fixturing. With all the variables involved, the best way to reliably test and compare is to do all the testing at one time on one flow bench with same setup on each head. Add highly competent journalists and technicians to that mix and you've got a fair, independent test that truly offers a valid comparison of cylinder heads. That's why we are so proud of how our AFR heads performed!

We have used the exact CHP flow numbers here. The flow test results and the quotes from the article are used by permission. If you missed the article, we will be happy to send you a complete copy of the 1998 CHP Small-Block Power Special with this article in it or go to www.chevyhiperformance.com to view the most current information available.

Chevy High Performance Magazine Talks About Choosing A Head

"There's much more to cylinder head selection than just choosing the head with the best flow numbers. In fact, as we've explained, large intake-port volumes with high peak flow numbers may not be the right choice at all. There are actually several criteria for selecting the best overall cylinder heads for your application. The best way to look at cylinder head flow is to closely examine and compare the entire flow curve from low lift to max lift.

If you must look at only one point, most airflow experts prefer to look at mid-lift flow. For street engines, airflow at 0.400-inch is a good place to evaluate all cylinder heads. The main reason for this is that maximum lift flow at 0.550- or 0.600-inch valve lift is at the ragged edge of most streetable valvetrains. More importantly, the valve is only at max lift once in the entire valve-lift cycle, while the valve achieves mid- and low-lift numbers on both the opening and closing sides of the valve-lift curve.

AFR Street Cylinder Heads

Here's what CHP has to say about AFR's 190cc Aluminum Street Heads: "If you're looking for great flow from a great midsize cylinder head, look closely at the AFR 190. This head offers the best flow numbers of all the Category 2 [180cc to 199cc] midsize heads with an outstanding exhaust port as well. The AFR 190 head offers great flow throughout the entire valve-lift range, not just at the peak-flow numbers. With a 72-percent E/I relationship, the AFR 190 offers great compatibility with almost any street or mild race combination. There's also a 195cc head that flows virtually the same but employs a larger intake-port opening for Victor Jr.-style intake manifolds. The 525hp 420ci small-block in this issue (see 'The New Riders of the Purple Sage') uses these heads with mild porting, so the potential is obvious.

Chevy High Performance Magazine
Exhaust Port Flow Test Results
180cc to 199cc Heads

"Pipe Dreams"

One of the most recent changes in cylinder-head flow-testing is the use of an exhaust pipe. The idea is to better simulate the way the exhaust port flows air. Our testing revealed that there is a significant difference in exhaust port flow when the same port is flowed with and without a pipe...Higher lift numbers tended to reflect the greatest change in flow between using the pipe and not using it. Increases were around 4 to 7 percent with the addition of the pipe.

AFR 210cc Race Ready Heads
Out-flow Every Challenger!

AFR Race Ready Cylinder Heads

Here's what CHP has to say about AFR's 210cc Aluminum Race Ready Heads: "When you get into these larger heads, the flow really starts to take off. The AFR heads measured a little larger than 210cc, but when you've got 240 cfm at 0.400-inch valve lift, who cares? The AFR 210 rocked to a max flow of 284 cfm at 0.700-inch valve lift right out of the box. With its E/I of 75 percent at 0.400-inch valve lift, it's hard to find something wrong with these heads. As street heads they're probably a bit large for a 350ci small-block, but they'd be a killer for a larger displacement Mouse motor, such as a 408- or 420ci thumper. When it comes to airflow, especially around 0.400- and 0.500-inch valve lift, the AFR is unparalleled among the heads we tested.

Chevy High Performance Magazine
Intake Port Flow Test Results
200cc to 220cc Cylinder Heads

Chevy High Performance Magazine
Exhaust Port Flow Test Results
200cc to 220cc Cylinder Heads