If anyone has a desk top dyno and some free time I was wondering if they could please help me. What do you think this combo would push in hp/ tq and how the power band looks.

-460-520 Stroker kit
SCAT 4.300" stroker crank
SCAT chromoly H beam rods
Fordged dished 10.5 to 1 compression .030 over pistons
Clevite-77 rod & main bearings
Sealed-Power moly rings

-Factory D0VE heads with some minor porting and polishing

-Comp Cams Competition K-Cam kit
Hyd. Cam
Duration @ .050": int/exh 253 deg./253 deg.
Lift: 585"/585"
112 deg. lobe seperation
Upgraded lifters, pushrods, valve springs, high energy double roler timing set

1.73 ratio roller rockers

-Weiand Stealth intake non CJ port matched to heads

-Holley 750 4bbl vac. secondaries, electric choke
or Holley 800 4bbl vac. secondaries, electric choke

-Exhaust
L&L Ultra Flow 1 3/4" primaries 4-1 header with 3" collectors to 3" flowmaster 40 origional series mufflers

-Nitrous power adder: NOS Brand Sniper 150 hp cheater system.

If someone can run this for me I would be very greafull.

 

If anyone wants to know this is going in a street/strip 67 f100 if the combo works out.

 

anyone?

 

The desk top dyno does not do ford big block engine very well my 521 is almost the same as your but i have a bigger cam and 2 inch headers and 3 1/2 collectors it would have 442 horse at 5000 rpms and 493 torque at 4000 rpms with the bottle 592 horse at 5500 and 836 torque at 2000

 

thanks for the reply, If you don't mind me asking what brand headers did you use? and what type of cam? also is your 531 in a truck?

 

it is a custom ground erson cam and the headers are hedman out side the frame headers and the engine was in the truck for a couple months but it is out know
The numbers from the post above are for yours not mine I forgot to tell you that

 

moore89

First - way, Way, WAY, WAAAAAAYYYYY too much cam for your combo! Comp Cams recommends a minimum of a 3500 stall converter, and gives a 6800 RPM upper powerband limit on the 305H cam grind. This cam would require radical head work, a single plane intake, and large tube headers to let the cam breath enough to maximize power. You would also need some major low-end work in order to keep the reciprocating assembly alive at the revs this cam prefers.

Here's the sim run using 9.5:1 compression, an 800 CFM carb, and presuming 1-7/8 primaries on the headers. I also presumed a .030 overbore (to 4.392 inches) and used the 4.300 inch crank throws. It works out to 521.2 cu in.

RPM / HP
2000 / 154
2500 / 206
3000 / 246
3500 / 299
4000 / 350
4500 / 388
5000 / 403
5500 / 392

RPM / Torque
2000 / 404
2500 / 432
3000 / 430
3500 / 448
4000 / 459
4500 / 453
5000 / 423
5500 / 374

The numbers are pathetic given the 521 cu inch displacement. It's indicative of just how mismatched the cam is to your combo.

For a street/strip combo, especially in a heavier vehicle like a truck, you would do well to condsider somnething like the Comp Cams Magnum 280H. It's much more streetable, still has a noticeable idle, and is much better suited to the combo you outlined.

Here are the sim results with the 280H

HP / RPM
2000 / 204
2500 / 257
3000 / 307
3500 / 356
4000 / 390
4500 / 398
5000 / 376
5500 / 325

Torque / RPM
2000 / 536
2500 / 540
3000 / 538
3500 / 534
4000 / 511
4500 / 465
5000 / 395
5500 / 311

You can see the broader, beefier torque curve at lower RPM. Where the previous combo was struggling to make 460 lb-ft at 4000 rpm, this combo starts off-idle with that much torque, and then proceeds to whip the pants off the first combo by 80 lb-ft (that's a 17% increas, in case you were wondering). And it does it in a more useful (for the street, at least) RPM range. It also maintains max HP (403@5000 vs 398@4500)

Since I already had the profile loaded, I also ran the sim using the Lunati Street/Strip hydraulic (P/N 00096). It beat the max torque numbers of the 280H by 17 lb-ft, and the max HP numbers by 6HP. And it did it in the part of the poweband you need most for a heavy street/strip vehicle.

HP / RPM
2000 / 209
2500 / 265
3000 / 314
3500 / 362
4000 / 395
4500 / 404
5000 / 384
5500 / 333

Torque / RPM
2000 / 549
2500 / 557
3000 / 549
3500 / 542
4000 / 519
4500 / 471
5000 / 403
5500 / 318

You can see that with nothing more than a cam change we have garnered you an extra 98 lb-ft torque. That's a 21% increase in power! That two-thirds of the increase you were after with your 150 nitrous shot, and it won't cost you a dime (unless you've already bought the first cam and now have to return it).

Remember that your engine is an integrated system. Everything has to work together for it to work properly. Going overboard in one area (and cams are the worst offenders) will not only cost you money, it will cost you significant performance! A fat, lopey cam sounds great, but it's worse than nothing if it's costing you 15 or 20 percent of your possible performance.

Brad

 

I disagree my cam is a 252 intake and 256 exhaust at .050 lift and .574 and .598 lift and it lopes but not bad and I drive on the street and it is in a 6500 lbs truck and I have ported dove C heads and a weland stealth intake the larger cubes help with the big cams
The desktop dyno is off on ford big block strokes try to build the ford motorsports 600 horse 514 and see what it comes too

 

moore89,I have Desktop dyno 2003 with the cam disk so I have over 4000 cams on file.I found your cam part # 34-337-4V8.I'm showing 458 hp @ 5500 rpm and 501 ft-lbs torque @ 4500 rpm.All the information was taken from all the cam specs itself so theres no guess work on any of the cam spec's.Everything was ran at seat to seat measurement's.This is the most accurate.I can print you up a full graph with hp and torque numbers with and without nitrous.I just need an email.Matt

 

Yep, too much cam for a build like this, IMO. I came up with 441HP @ 5000 and 486TQ @ 4000 with the Comp 305H cam. I ran the same combo with the cam I have in my 466 (Lunati 41605 Solid) and came up with 464HP @ 4500 and 597TQ @ 2500,3000 and 3500!! I also used the port flow numbers from my D0VE heads with 2.19" Intake and 1.70" Exhaust valves:

• .200-- 155 I / 108 E
• .300-- 227 I / 136 E
• .400-- 278 I / 170 E
• .500-- 299 I / 182 E
• .600-- 311 I / 186 E
• .700-- 316 I / 186 E

The 305H cam would be a good choice for an engine running 11-1 comp, aluminum heads, single plane intake, 950+ cfm carb and large tube headers and going into a race vehicle.

 

Another thing,it says the cam is for a jet boat application with a B impeller flat bottom or hydro bracket for drag racing.Say's likes tunnel ram.

 

It's the head flow specs built into the defaults that blow the numbers. To duplicate the flow numbers for the Motorsports SJC heads (appx 345 cfm intake, 225 cfm exhaust) you have to use the "Canted/Rectangular Ports, Fully Ported" option. None of the "Wedge" options duplicate the SCJ head flow characteristics.

If anyone has a bench card for a couple of difference variations on the stock Ford heads I would love to have the numbers so I could set up a specific profile for them. Researching flow numbers to get the DD combos right is a pain in the behind.

Brad

 

Very easy Brad.....Scott J at http://reincarnation-automotive.com/ has most every head in stages from as cast to full porting listed. He asks $25 to get unlimited access to his 429/460 data base, and its the best $25 you will spend on your engine. I would post his information, but I fear that would be stealing his hard earned information and make him block my account :]

 

Thanks!