Grumpy-engine builder-engine dyno- opinion

[Guest needwaymorespeed]

Ive ben crunching #s on desk top dyno and was hoping you could confirm these

406 sbc 850 carb 1.750 headers 10.5 comp

single plane victor jr. afr 195 heads

intake exhaust

.100 71 67

.200 144 121

.300 208 157

.400 244 188

.500 262 202

.600 261 211

 

the cam is crane hydraulic roller hr-306-2s-10.86

specs are

.558 lift intake and exhaust

ivo 15 ivc 45 exo 59 evc 9 at .o50

110 lobe sep

desktop dyno puts out

2000 167 437

2500 220 463

3000 278 487

3500 342 512

4000 402 528

4500 459 535

5000 523 524

5500 523 500

6000 522 457

6500 503 406

7000 467 350

 

then if I change the heads only with a set of heavily ported dart pro-1 that flow

 

int exh

.100 80 67

.200 136 114

.300 197 160

.400 253 197

.500 287 217

.600 301 227

I get these figures

 

2000 163 428

2500 214 449

3000 269 471

3500 333 500

4000 398 522

4500 460 537

5000 507 533

5500 540 516

6000 552 483

6500 551 445

7000 523 392

7500 493 345

 

does that look right to you I was expecting bigger #s from the dart pro 1s, cant hardly see running the darts at 25 cc intake runner size bigger when the afrs are so close.

am I missing something here?? Is that cam too big for a street strip warrior?

thanks guys help me decide. the heads are rel close to the same money. will that hyd. roller cause problems

.I was real surprised by the two comparisons

Curtis

[grumpyvette]

ok first your not realy comparing apples to apples here, first your cam only has .558 lift so the real flow charts are,

rpm....pro-1.......afr

.100 71 67.....100 80 67

.200 136 114...200 144 121

.300 197 160...300 208 157

.400 253 197...400 244 188

.500 287 217...500 262 202

.558 295 212...558 262 207

USEING YOUR FIGURES

523hp->552 hp is a 9.5% DIFFERANCE (CLOSE ENOUGH SINCE THE PRO-1 HEADS average INTAKE FLOW IS 222 VERUS 215CFM FOR THE afr A 9.7% DIFFERANCE.

 

NOW AS FAR AS THOSE HP ESTIMATES GO MY DYNO PROGRAM SHOWS 500hp/506 tq for the afr and 538hp/532tq for the PRO-1 heads (a 9.3% differance BTW) and no the cam is on the ragged edge but not TOO big for a street strip engine as long as your not thinking of a daily driver and are only useing it for brief trips,the cam Im useing is the 119661 hydrolic roller and its really just a little to wild for long trips (230/238 dur .539/.558 112LSA) that cam in your combo will get you 505hp/527tq with the PRO-1 heads and 475hp/530 tq with the AFR according to the computer.

[John Scott]

Great #s! Sounds like a torque monster! One of the reasons I went with the 215s was the similar port cross section to the AFRs. They still maintain the low end velocity of the smaller heads, note the flows at .200, .300, .400. Something my builder has passed on, that when you get a good exhaust to intake ratio, you won't need the typically wide spread of duration of most off the shelf cams, which try to make up for lesser flowing exhasut of most heads. These heads, like the AFRs would probably benefit from narrowing the spread to about 4 degrees. Tayloring a cam's lobe profile, accel. ramps, to the flows throughout the valve lift, i.e. custom grind, is one more way of getting the most potential out of your head.

JS

[Guest needwaymorespeed]

Thanks guys

input very appreciated

Curtis