Ok guys, since the so called "rzr head goo roo" didn’t know any rzr head flow numbers my guy did some investigation for you rzr owners who would like to know…below are the actual flow bench results on an untouched 1000 head and then his ported 900 head, I will get the before numbers for the 900 soon, All these numbers are performed on a calibrated flow bench at 28" of water on the column and max flowed upto .500" of valve lift…

Stock flow for 1000 rzr head below

.500 lift 288 cfm
.450 lift 281
.400 lift. 271
.350 lift. 259
.300 lift. 330
.250 lift. 198
.200.lift. 166
.150 lift 133.5
.100.lift. 91

Ported rzr 900 head below

.500 lift. 303 cfm
.450 lift. 300
.400 lift. 288
.350 lift. 272
.300 lift. 243
.250 lift 215.5
.200 lift. 178
.150 lift. 138
.100 lift. 92

the 1000 head will outflow the 900 head, because the port is .250 wider. The only problem is the chamber needs alot more work than the 900 head This just proves that most of these guys are just guessing, dont know how to port, or dont have a flow bench