I think the only standard port head that tops these As-delivered were the old Chapman Stage VI 260 (which I think JohnRR sent to Dwayne the same time I sent my Chap 265 MW's) And the Chapmans were Raised ports and long valve heads that need special rocker gear. I think they went 360 up around .600-.650, may still be in the Moparts archives. Not sure they were any better than these at .400-.450 though.
I can provide some comparative data from Dwayne's current bench (a Saenz 600) tested on the same 4.375" bore:
A. My old PRH-ported MP Stage VIs w/ 2.14" intake valves and small 215 cc runners (w/o RB adapters added). On a 10.8:1 CR RB 452 short block using a modified MP M1 intake, my BG "825" carb, 2" headers and a 266 at .050" x .600" x 108 LSA SFT cam, it made around 610 HP & 570 Tq on Dwayne's dyno.
Lift -- Int / Exh (no flow tube)
.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
B. My Hughes CNC-ported 1st-generation Edelbrock Victors w/ 2.20" intake valves and an estimated 270 cc runner volume (adjusted down about 40 cc for the built-in RB adapters). Like the Chapmans, these have raised ports and need special-offset intake rockers.
Lift -- Int / Exh (no flow tube)
.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
At the same CR as the MP Stage VIs and the .650" roller version of the SFT mentioned above, I'll take a s.w.a.g. and say I'd expect to see 640+ HP from the Trick Flows on the same RB 452 short block as the Stage VIs were tested, between the different heads and switching to a roller.
But it's all just educated(?) guesses until someone puts 'em in service.
