[bracketracer]

Ok heres my current combo, 350 two bolt mains, bored 40 over flat top pistons, stock crank and rods, heads 461 double humps, 64cc,202 160 valves, roller rockers, cam is a elgin solid flat tappet,256 264 @50 504 504 lift 106 lobe seperation. victor jr intake, 650 holley quick fuel vac secondarys. 9.8 compression. Headers are 1.75 open headers. Please dyno this. Also my engine is apart so i was wondering what kind of power it would make with this cam comp cams extreme energy advertized duration 284 296, 507 510 lift,2300 to 6500 rpm.I also wondered about the 292H comp cam, Please dyno thes combos thanks for your help.

[ericnova72]

Either of the hydraulic cams you have listed will be a step down in power from the solid that you have now. Why do you want to change? Unhappy with what you have now?

[bracketracer]

just courious its a street strip car and that big solid is kinda annoying after a while its still loping at 3,000 rpm. Its in a 55 Chevy 2dr wagon, turbo 350 4,000 stall 486 gears. Best E.T 60ft 1.65 12.37 108 with a nice tail wind. I probly shouldnt change what works. I been trying to figure how much horse power my current combo is. I found an ET calculator and with my car weight which is 3860 and my mph it says 400 to rear wheels. I dont see how that is.

[cobalt327]

Looks like 390-400 HP on my old Moroso calculator, too. Does this seem low to you?

108 MPH equated to a 12.1 ET w/perfect traction and set-up.

These things always were a source of debate when bench racing.

[bracketracer]

I figured it was close to 400 at the flywheel. was the 390 to 400 at the flywheel? I couldnt see it being much more than that with the stock 461 heads.

[ericnova72]

Maybe switch to a lower duration but higher lift solid?

Especially to a straight(or close)pattern on the duration. More torque down low but will still breath up top.

4.86 is a pretty deep gear, How tall are your tires?

Deck the block and mill the heads while it's apart, if you haven't already, to bump up the compression to 10.5-1.

What was the previous post trap RPM?

[bracketracer]

Block was decked, running 28x10.5 et streets, its turning 6300 at the big end.

[ericnova72]

Got a 60 foot time?

Any port work to the heads?

[cobalt327]

Originally Posted by bracketracer

I figured it was close to 400 at the flywheel. was the 390 to 400 at the flywheel? I couldnt see it being much more than that with the stock 461 heads.

I've always azs-umed the Moroso calculator was RWHP.

When checking the performance of a Camaro I had w/a 455 Pont, it estimated the HP to be about 325 at 108 MPH, weight of 3700 lbs.

This was w/ported 6X 400 heads, healthy cam, headers, etc. I'd be surprised if it only made 325 HP at the flywheel.

[bracketracer]

Car 60fts 1.65 ussually, heads are bone stock with a nice valve job bronze guides and the goodies for pump gas. Im suprised that it could be 450 at the fly wheel from reading posts on here about how crappy stock double humps are. Anyone dyno this yet? Dont they claim you loose around 20 percent to the rear wheels ? If thats true then im looking at 460 hp at the fly wheel on pump gas with crappy heads. LOL

[cobalt327]

Yeah, the Moroso deal is screwy. I wouldn't think (no insult intended) that your combination made 460 BHP, either. But in some cases it seems close, like w/my 455 having 325 HP at the rear wheels.

It can be thrown off if any of the variables are off- weight, speed or ET. And invariably, there are different results when using ET to calculate HP or using 1/4 mile top speed.

It's more useful as a gear ratio/rpm/speed/tire diameter and bore/stroke/displacement and CR calculator- those are "hard" numbers, not open to interpretation.

But before Desktop Dyno, that was about all there was that could be held in your hand other than a regular calculator and reams of formulas.

Mine is so old, cracked and yellowed that it'll soon be history. Won't toss it, just retire it.

[techinspector1]

Get me some flow numbers on the heads and the timing events on the cam and I'll run it for you.

[ericnova72]

A well sorted out combination may only lose 15% through the driveline, which would put you near 440 hp flywheel. I could see this being true for you.

[bracketracer]

ok flow numbers, there 461 castings, 161 runners, 202 160 valves.

lift intake exhaust
100 50 54
200 119 91
300 167 121
400 198 134
500 215 139
600 219 142

cam specs elgin solid lifter, 256 264 @50, 504 504 lift, 105 lobe sep. cant find cam card.
350 bored 40 over, stock crank and rods, block was decked, flat top pistons, 9.8 compression. intake is victor jr, 650 holley carb, headers are 1.75 full length into 3 in. collectors. Thanks John

[techinspector1]

OK, in post 1 you said 106 LSA, in post 14 you said 105 LSA. I went with 106 because it is more common. Figuring the most common intake centerline at 102 and exhaust centerline at 110 and figuring backward, here are the data....
Elgin solid flat tappet
Intake duration @ 0.050" 256
Intake opens 26 degrees BTDC
Intake closes 50 degrees ABDC
Intake lift 0.504"
Intake centerline 102 degrees ATDC
Exhaust duration @ 0.050" 264
Exhaust opens 62 degrees BBDC
Exhaust closes 22 degrees ATDC
Exhaust lift 0.504"
Exhaust centerline 110 degrees BTDC
Lobe separation angle 106 degrees
Overlap 48 degrees

Pull #1
This combo is run just as you stated....
RPM HP TQ
2000 108 285
2500 160 337
3000 203 356
3500 256 384
4000 312 409
4500 362 423
5000 394 414
5500 421 402
6000 433 379
6500 431 348
7000 402 301
7500 382 267
8000 329 216

Pull #1A. Same as above, but changed to 3.750" crank. Motor is now 385 CID. Increase CID has increased the static compression ratio to 10.5:1 with the same heads, piston deck height and gasket thickness as we had with the 9.8:1 static compression ratio motor. The hp and torque change isn't as dramatic as you might have thought with another 28 cubic inches and 0.7 increase in the SCR, probably because the heads are stalling out with the increased cubic inches.
RPM HP TQ
2000 123 323
2500 179 377
3000 226 395
3500 280 420
4000 335 440
4500 383 446
5000 414 435
5500 434 414
6000 437 382
6500 420 340
7000 367 275
7500 339 237
8000 285 187

Pull #2
Changed to L31 Vortec heads, re-installed 350 crank and re-established 9.8:1 SCR. All else the same.....
RPM HP TQ
2000 107 280
2500 156 327
3000 195 342
3500 250 375
4000 311 408
4500 369 430
5000 411 431
5500 440 421
6000 458 401
6500 460 372
7000 440 330
7500 422 295
8000 373 245

Pull #3
Max-out L31 pull. Stock heads, 170cc runners, 1.94"/1.50" valves, springs and retainers changed to work with this cam.
Changed to 800 cfm carb, retarded cam 2 degrees, swapped rockers to 1.6 both sides, large stepped-tube race headers.
Edelbrock RPM intake. And no, that hp gain from 4000 to 5000 is not a mistake. The motor actually does gain 202 hp from 4-5. On the graph, the line is almost vertical from 4-5.
RPM HP TQ
2000 79 207
2500 123 258
3000 166 291
3500 217 326
4000 280 368
4500 392 458
5000 482 506
5500 492 470
6000 487 426
6500 473 382
7000 440 330
7500 411 288
8000 365 240

Pull #4
Changed back to 461 heads, 800 cfm carb, large stepped-tube race headers, 1.6 rockers both sides, retarded cam 1 degree. This is maxed out with the 461 heads. Further improvement will require a head change.....
RPM HP TQ
2000 92 241
2500 158 331
3000 209 366
3500 261 391
4000 318 417
4500 373 435
5000 416 437
5500 444 424
6000 453 397
6500 440 356
7000 421 316
7500 393 275
8000 338 222

Pull #5
I could have picked just about any aftermarket head and improved on the Chevy castings, but wanted to see these Edelbrock 185cc runners on paper with a strong cam such as the one used here. Everything is the same as above except the heads......It's interesting to note that under 4000, the motor made more hp and torque with the 461 heads. Just depends on where you want the power and where the converter stalls.....
RPM HP TQ
2000 84 222
2500 149 314
3000 196 344
3500 251 376
4000 316 415
4500 384 448
5000 445 467
5500 488 466
6000 519 454
6500 528 427
7000 528 396
7500 520 364
8000 486 319

Pull #6
We often see arguments over the intake manifold to use in a street motor. Now, this is not a street motor, but changing only the intake to a RPM shows exactly where the tip-over comes in....6000 rpm's with a long cam in a properly set up motor such as this one. If a guy were using a shorter converter that stalled at maybe 3000 behind this motor, he may go faster with a RPM than a Victor Jr. because he would be gaining in the 3000 rpm spread between 3000 and 6000 more than he would in the 2000 rpm spread between 6000 and 8000. Just something to think about....
Changed to RPM intake, all else same as above....
RPM HP TQ
2000 96 252
2500 157 329
3000 206 361
3500 263 394
4000 329 431
4500 397 463
5000 459 482
5500 493 470
6000 518 453
6500 521 421
7000 512 384
7500 499 349
8000 464 305

Pull #7
Still thinking that there had to be 500 ft/lbs of torque here somewhere with relatively inexpensive heads, I left the RPM intake on and changed heads to Patriot 195's, all else the same....
RPM HP TQ
2000 80 209
2500 125 263
3000 186 326
3500 270 405
4000 358 470
4500 427 499
5000 480 504
5500 500 477
6000 518 453
6500 519 419
7000 505 379
7500 492 344
8000 451 296

That's about all the power I can wring out of a 357 Chevy. I tried another 6 cams and got nowhere. This is the perfect little mule motor to try different stuff on. Let's leave the short block as it is and if any of you other fellows want to try different heads and stuff on it, let me know.

Pull #8.
OK, pullin' out all the stops here. All hands on deck. Hide the women and children and sound General Quarters.....
385 Chevy, 4.040" X 3.750. 10.5:1 SCR. Large stepped-tube race headers. Victor Jr. intake with 850 carb. Patriot aluminum heads with 225cc intake runners. CompCams 12-517-5 solid flat tappet drag race grind, 296TLS-6, 296/304, 266/274, 0.570"/0.590", installed retarded 1 degree. Intake centerline 107, Exhaust centerline 105, Lobe separation angle 106. Timing events at 0.050",
Intake opens 26 degrees BTDC
Intake closes 60 degrees ABDC
Exhaust opens 62 degrees BBDC
Exhaust closes 32 degrees ATDC
Valve overlap 58 degrees.
RPM HP TQ
2000 118 311
2500 173 364
3000 212 372
3500 271 406
4000 344 452
4500 419 489
5000 487 511
5500 544 520
6000 582 510
6500 607 491
7000 620 465
7500 613 430
8000 601 395