Undercover Porting Flow Figures

Compare Stock Ports to Various Combinations of “Undercover Porting”

How we gathered the flow numbers in this catalog:

SuperFlow 600The flow numbers are gathered from dozens of tests on each particular head. After we have a wide cross section of tests, the flow figures are averaged to achieve a fair baseline. True, some ports may, on a particular casting, flow 2 to 4 percent more than our average base line. However, the next port (or the next head) may be down more than 4 percent. This is especially true with stock cast iron castings. Also, the head’s flow numbers may change over years, due to changes in production. All of our flow testing is performed at 28” of water with a SuperFlow 600 flow bench, Flow Pro software from Audi Technology and the flow bench equipment displayed in this catalog.

Chevy Vortec Bow-Tie
Stock vs. “Undercover” Ported

Valves: 2.02 x 1.60

Lift Stock
Intake
“UC”
Intake
Stock
Exh.
“UC”
Exh.
.100  62  64  49   50
.200 128 135 106 110
.300 183 188 134 140
.400 225 232 152 165
.500 235 251 161 179
.600 236 252 163 183
Bow-Tie Stock vs. “Undercover”

Valves: 2.02 x 1.60

Lift Stock
Intake
“UC”
Intake
Stock
Exh.
“UC”
Exh.
.100  63  68  58 60
.200 126 133 113 118
.300 180 186 135 145
.400 209 224 143 160
.500 212 236 145 168
.600 211 245 147 173
World Prod. Sportsman II Stock vs. “Undercover”

Valves: 2.02 x 1.60

Lift Stock
Intake
“UC”
Intake
Stock
Exh.
“UC”
Exh.
.100  64  68  60  61
.200 130 139 107 116
.300 186 196 126 146
.400 214 231 139 161
.500 230 245 147 169
.600 233 252 148 174
World Products S/R Stock vs. “Undercover Ported”

Valves: 2.02 x 1.60

Lift Stock
Intake
“UC”
Intake
Stock
Exh.
“UC”
Exh.
.100  64  68  53 57
.200 130 144 110 108
.300 175 193 126 136
.400 191 211 132 147
.500 196 228 135 154
.600 196 235 135 157