I think JohnRR's Chapman VI's also went right at 350 peak too and with better .200-.600's (from Fast's bench) than any other standard ports I can remember. I think below .350 or so they were even better than my MW 285's. Wish I'd have known when he was selling those...and those numbers were more than 12 years ago. I was thinking at the time....300 cfm at only .450 lift is pretty amazing if you think about it, even a stock replacement Mr sixpack cam in a 10:1 440 would make some serious power and have 14" at idle and a still streetable .557 or .590 purple shaft in a hot 470 would be killer with those .500-.600 numbers.
from the Tech archives:
Chapman CNC'd MP Stage VI 260cc's:
Lift" I/E
.100--71.5/58.2
.200-150.0/118.6
.300-219.4/180.0
.400-278.7/219.4
.500-323.6/233.9
.550-338.9/240.3
.600-352.3/243.5
.650-348.5/246.7
.700-348.5/249.9
.750-348.5/251.5
.800-348.5/253.1
I'm sorry... can't help it... must... post... more... cylinder... head... data...
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MP (Mopar Performance) Stage VI heads vs Edelbrock Victors (both prepped & ported significantly from "as cast"):
-------------------- MP --- EV
Intake valve ------ 2.14 - 2.20
Exhaust valve ----- 1.81 - 1.81
Intake runner cc -- 245* - 294
Intake Avg CSA ---- 2.39 - 2.76
Intake Min CSA ---- ~2.2 - 2.66
* Includes volume from intake spacers required to use on RB block (440)
III. Flow data from same Saenz 600-class bench tested on 4.375" fixture:
INTAKE - MP --- EV --- Delta
0.100 -- 69 --- 75 ---- 6
0.200 -- 143 -- 151 --- 8
0.300 -- 213 -- 220 --- 7
0.400 -- 262 -- 280 --- 18
0.500 -- 293 -- 326 --- 33
0.550 -- 305 -- 338 --- 33
0.600 -- 307 -- 346 --- 39
0.650 -- 307 -- 350 --- 43
0.700 -- 307 -- 355 --- 48
0.750 -- N/A -- 347**
EXHAUST - MP -- EV --- Delta -- EV w/ 2" pipe added
0.100 -- 52 --- 55 --- 2
0.200 -- 108 -- 116 -- 8
0.300 -- 146 -- 155 -- 9
0.400 -- 181 -- 194 -- 13
0.500 -- 211 -- 223 -- 12 ----- 238
0.550 -- 222 -- 233 -- 11 ----- 249
0.600 -- 231 -- 241 -- 10 ----- 259
0.650 -- 237 -- 247 -- 10 ----- 267
0.700 -- 243 -- 252 -- 9 ------ 274
0.750 -- 255 -- N/A ---N/A ---- 278
** Drop-off above .700" is suspected of being due to the chambers' CNC work laying back the plug-side wall too much. The same drop-off resulted when tested at 15" / 28" / 35" H20, yet without any change to relative flow #s for each depression level. A hand-ported casting that was used as a flow bench "guinea pig" didn't have the chamber pulled back as much as the CNC'd chamber program, and it did NOT have the same issue w/ dropping off at .700".
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