My flow bench is a small-capacity SuperFlow 110. Porter Racing Heads' is a Saenz 600 that can pull 28", instead of testing at a much lower pressure and applying conversion factors like I do. These tests of my Hughes CNC-ported Victors and PRH-ported MP Stage VIs were done w/ a 4.375" bore adapter, except my test of the Stage VI was on a 4.25" w/ the head offset to unshroud the valve. I'll retest it on a 4.375" later to see what difference it makes.

None of the exhaust tests used a "flow tube", which I've seen add 20+ cfm at high lifts over not having one attached. Also, I couldn't find an exhaust test for the same Stage VI intake port that Dwayne tested, so I've provided exhaust data from a different cylinder on the same head.

My Victor test #3 cylinder:
Lift -- Int / Exh
.100 --- 73 / 54
.200 -- 155 / 105
.300 -- 224 / 162
.400 -- 282 / 200
.500 -- 317 / 219
.550 -- 329 / 229
.600 -- 343 / 236
.650 -- 346 / 244
.700 -- 350 / 247

PRH Victor test #3 cylinder:
Lift -- Int / Exh
.100 --- 75 / 58
.200 -- 169 / 109
.300 -- 237 / 157
.400 -- 280 / 201
.500 -- 318 / 229
.550 -- 329 / 239
.600 -- 341 / 246
.650 -- 347 / 253
.700 -- 345 / 256

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My Stage VI test #1 intake/ #3 exhaust cylinder:
Lift -- Int / Exh
.100 --- 68 / 52
.200 -- 140 / 102
.300 -- 200 / 148
.400 -- 250 / 183
.500 -- 288 / 207
.550 -- 305 / 217
.600 -- 305 / 224
.650 -- 308 / 229
.700 -- 310 / 236

PRH Stage VI test #1 cylinder:
Lift -- Int / Exh
.100 --- 69 / 53
.200 -- 143 / 108
.300 -- 213 / 146
.400 -- 262 / 181
.500 -- 293 / 211
.550 -- 305 / 222
.600 -- 307 / 231
.650 -- 307 / 237
.700 -- 307 / 243

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Something else to note: Probably because of the significantly shorter distance between the mounting surface of the head adapter and the blower motor in the bench housing, the exhaust readings taken on a SF-110 can (and do) vary when the cylinder is tested w/ the exhaust port facing the bench and then reversed to face away from the bench. Dwayne saw the same thing w/ his old 110, but says his 600 doesn't show the same behavior.

Both of my tests above were done w/ the heads' exhaust ports facing the bench. When retesting the same Stage VI #3 exhaust after the head was flipped around, it picked up the high-lift by as much as 12 cfm in comparison and put the #s right in line w/ what Dwayne got for the #1 port.

Lift -- 1st / 2nd (turned around)
.500 -- 207 / 211
.550 -- 217 / 223
.600 -- 224 / 233
.650 -- 229 / 240
.700 -- 236 / 248

When I get some time to do additional testing, I'll retest the Victor exhaust port turned around and see how much of the difference between Dwayne's bench and mine is still there.

Something else I wanted to comment on. I know if I was doing this for a living that I'd definitely want a "high powered" flow bench capable of pulling 400+ cfm w/o having to mess w/ correction factors, etc. However, there are people who say that if you have to apply correction factors to your results that they can't be compared to a "real" flow bench that doesn't use them. I think for the level of heads shown here, this at least shows that a small(er) bench's results aren't necessarily invalid.

I can add that I have seen the same heads on the following benches that are all within a max of 1% of each other:

Superflow 600
Superflow 100 with conversion math.
HOME BUILT with Audie components with conversion math.

Are those the standard port cnc victor heads? Thanks

Chamber shot of Victors w/ CNC work and milled back down to 76 cc. Valves are the Edelbrock-supplied 2.20" / 1.81" pieces.

Same view for Stage VIs w/ chamber work and milled back down to 78 cc. Valves are Ferrea 6000-series 2.14" / 1.81" supplied by Dwayne when he did the heads initially back in 2000.

View of Victor intake & exhaust bowl work.

Same view for Stage VI.

Intake entries for Stage VI... slightly smaller entry size and much smaller runner volume compared to CNC Victors. (My apology for crappy picture.) This view is through the RB intake adapters which Dwayne mounted to the heads using countersunk screws to enable consistent positioning and port matching.

The volume difference cannot be considered alone. The cast in "spacer" on the Victor adds length and a lot of it. Look at cross sections to determine the "size" of the port. The Victors have an ugly chamber don't they? J.Rob

Hughes says their CNC work leaves the intake runner around 310 cc, IIRC. These Stage VIs when measured w/ the RB spacers came up about 245 cc (the spacers added 30+ cc to the runner volume). If you factor out the volume of the cast-in "spacer" on the Victor, it's still going to be a 270-ish runner compared to approx. 215 measured for this Stage VI w/o the RB adapter.

I don't have cross section measurements, but the longer valves used w/ the Victors allow for a much deeper bowl and taller short turn. It's definitely a "bigger" port all around than the Stage VI.

Speaking of Chapman Stage VIs, here's a look down the 260 cc version's intake runners.

FWIW, here's what Chapman advertised this particular head to flow:

Lift Intake Exhaust
.100" 71 55
.200" 157 112
.300" 230 177
.400" 290 211
.500" 325 233
.600" 351 242
.700" 351 252

Awesome thread Bra....Oops sorry Cap'n.

Useful tech info with pictures!
I feel like I've stepped into a time machine and it's Moparts 1998 again

Rumor has it Chapman is out of business??? True?
I've never had their contact info and couldn't substantiate the rumor....