I'm not a big believer in Desktop Dyno, but I'd like this combo plotted, if you don't mind.
SBC, 4.06 x 3.75, 10.10:1, 175cc, 1.94/1.60, 0.100"=65/57, 0.200"=133/114, 0.300"=188/149, 0.400"=223/167, 0.500"=238/177, 0.600"=238/181. Single plane intake, 850 cfm carb, large tube headers with mufflers, cam is hydraulic flat tappet, rockers are 1.50:1, cam specs are: duration at 0.050" of 224/224, lobe separation angle of 110, lift of 0.474/0.530 ( I know this seems improbable, but that's what I want input )
Please post the graph, plotted from idle to 6500. Once we see the results, I'll explain the combo. Thank you very very much.

 

Oops, forgot: Intake center line of 107 degrees. So the IO is 5 before, the IC is 39 after, the EO is 45 before, and the EC is 1 before.

 

No problem at all and here ya go.

The cam was installed straight up too just FYI.

 

Thanks again. I was expecting a fairly flat torque output from 3000-4000, with HP peak just after 5500.
This build is unremarkable, except that I'm speccing it for a high-elevation canyon cruiser with a T56 and the wrong gearing.
I have one more, if you're willing. It's a 350 with ported 416 heads.

 

4.000 x 3.480, 9.50:1, 165cc, 1.94/1.60, 0.100"=63/40, 0.200"=126/91, 0.300"=178/136, 0.400"=206/153, 0.500"=214/169. everything else same as above except cam. 210/214-111@108, 474/474 and it should be done by 6000 rpm.

 

No problem, I'll DD whatever you need. Do you have the valve timing for this cam?

I only ask because it looks "off" and if I use a generic Summit grind of like duration it's picking up 40hp and 500-1000rpm. Otherwise it's falling on it's face just after 5000rpm.

 

I guess you've noticed how the ones I'm asking for simulation of are not giving wonderfully good results. If I thought they'd do well, I'd actually build them. I'm hoping to illustrate that the combos that people PM me to ask about are disappointing them for good reason. The girl with the 388 above thought she should be around 475 HP and over 490 ft-lbs. She's using a set of my stage 2 Vortecs, when I suggested she needs AFR 180 heads to get near her expectations.
This combo is from a boy who's about to graduate from the local university. He thought this cam was wonderful because it has a slight idle, it feels best in the mid-range, it runs pump gas, it has clean emissions, it uses stock rockers and cheap springs, and is, in theory, well matched to the heads. It really should do a 5500 up-shift.
The IO is 3 after, the IC is 33 after, the EO is 41 before, and the EC is 7 before.
Please post the graph for that.
And since so many guys do 305 heads on a 350, if you want to overlay your 40 horse Summit cam, that might be enlightening. I'm guessing it's the SUM-K1103, with 442/465 lift and timing events of: IO=1 after, IC=35 after, EO=48 before, EC=4 before. But I bet you'll see better results from a COMP cam with these specs: input as hydraulic flat tappet, 487/495, IO=2 before, IC=36 after, EO=45 before, EC=1 before.

 

DD tends to be too optimistic when you choose the roller cam option. That's why I prefer to tell it HF even when the real cam is HR.
Also, Vizard is correct that when an engine is flow-limited, you should use tighter lobe separation angles. It does make for peakier power bands, but in-car results are still better.

 

You are spot on, it looked wrong and still does

It's not terrible but lots of room for improvement.

The summit cam was just what you thought, the 1103 dual pattern. It's not exactly 40hp that's what I thought at a glance but it is 33peak but look at the difference over peak.

I worked up that comp cam real quick too but didn't add it because it gets confusing with 2 overlays. But it did make slightly more power through out the power band, the summit cam peak 3 more HP but that was the only point it made more power.

 

Have you tried to use the cam interation feature where it will go thru hundreds of cam valve timing events to find max torque or max hp within + - 500 rpm of the current peak hp rpm or torque rpm? You have the option to find cam for best torque or best hp.

Its a neat feature. I find DD to be optimistic too but I select small tube headers with mufflers to tame it down some. I ran my 383 combo on there and messed around until I found a setup that best simulated what I "thought" the motor made on crank based on the numbers it made on the dyno and how it ran at the track. SEems like the smaller exhaust with mufflers makes it more realistic.

 

The 1103 loses low-end mostly because of the early exhaust opening combined with more overlap. Of these 2 cams, the COMP has the potential for more MPG, possibly as much as 3 MPG better, because it can pull a significantly taller final drive ratio. But even so, it's not a great combo.
I myself don't like the iterative feature, because left to it's own devices, it recommends excessive splits that don't do so well in a real car.
I did once try it, with a custom cam from Crane. Never again.
I don't have any other Chevy combos that I'd like to see, just a couple of Fords, but that's not relevant to third gens.

 

I also find Desktop Dyno will provide startling different results when changing the exhaust system profile.
Very FEW installed engines will ever match the open header results on DD. Try making the switch to headers with mufflers or better yet, manifolds and see how the results change. Far more representative of the what the real world results are.
My proof is in DD results vs time slips.

 

Realism is why I asked for large tube headers with mufflers. It's also why I asked for a single plane. That comes the closest to the RPM AirGap.

 

I think it's as accurate as you can get with out dynoing. And just like a dyno air quality plays a lot into what the outcome is. You can vary 20-30 hp easy due to air and DD2k doesn't account for this. Add in accessories and you are loosing another 10-20hp or so. Maybe they'll add in air quality and accessories in DD2012.

It's not showing you what you got it is showing you what you could have all things perfect. Things like human error and tune play a big part in it too weather we want to admit it or not, I know being "right" is the male disease.

 

IF you saved the 383, please overlay a 220/230-110 at 107, 480/510 cam. The IO=3 before, the IC=37 after, the EO=48 before, and the EC=2 after.
This should broaden the powerband.
Then, please try the exact same thing but as a 9.2:1 355, and the cam a 214/224-110 at 107, 474/503. IO=0, IC=34 after, EO=45 before, and EC=1 before. This should give surprising mid-range torque.
Again, thank you very much.

 

The first one is the 383 and the dotted line is the newer cam. Was the exhaust lift a typo in the first one?


That 350 looks nice too (both have great mid range power). I was messing with it and it really liked a full point more compression. It was peaking at the same power as the 383 but 500rpms or so later with 10.2cr.

 

I use the Pro Racing Sim suite of programs (as well as DD2k)
Build an engine in Dyno Sim and install it in a chassis using Drag Sim. Drag Sim has choices for Air Altitude Density. You can see the obvious effect atmospheric changes have on et/mph and horsepower.
I suppose like an engine dyno, the weather of the day has less effect on the results (of DD2k) as the the testing in done under a more controlled condition.

 

The Vortec 350 actually has 10.12:1, but since we are at 4500' elev, it cranks the same psi as if it was 9.22:1 at sea level. And this build does get driven to sea level, where it must still run safely on pump gas. But the owner lives here 10.5 months of each year, so power at sea level is nothing.
I just multiply the dyno results by 0.83, and that's very close to the real crankshaft results up here.
I truly love that 350. The top end surprises me, and the low end is better than the 400 hp Vortec 350 in the best builds sticky in swap. Maybe you should superimpose the 10.2:1 results.
The 383 needs better heads.

 

I don't really expect anyone to do these 2, either Doom or Skinny or anyone else, because they're Ford, but here they are anyway.
4.060 x 3.850", 10.10:1, 2.02/1.60, 850 carb on a single plane, hyd flat cam,
enter 1.5:1 rockers, large tube headers with mufflers,
The mild combo flows: 0.100"=72/60, 0.200"=154/121, 0.300"=208/159, 0.400"=254/184, 0.500"=271/193, 0.600"= 274/199. Because the heads are RHS 180. The mild cam is 220/228-110 at 107, 578/590 IO@3 before, IC@37 after, EO@47 before, EC@1 after.
The wild combo: flow at 100 unknown, because these are AFR 12R 190, so use 72/60, 0.200"=152/121, 0.300"=211/158, 0.400"=257/193, 0.500"=290/214, 0.550"=301/219, 0.600"=310/222, and the cam is 226/234-112 at 109, 555/565. IO=4 before, IC=42 after, EO=52 before, EC=2 after.
I need something in my '89 Mustang LX, and I have the short-block built except for a cam.
Thanks.

 

I really expected this SBF to peak higher but I think that at this high of HP the generic "muffler" is suspect of restriction. They may be using flowmaster, who knows?

 

I really do thank you for making the efforts. The mild version doing 450 horses is decent.
As with the 383 above, these builds want more overlap, but that hurts both emissions and trying to idle down the interstate. These builds would be better for a 347 than a 399. Especially in a bantam weight car. But to get top end, there's a good-sized ATI ProCharger under my bed.

 

You're welcome you've helped me more then I could ever help you, its the least I can do really.

The torque curve on that mild SBF is very nice looking. It would probably win on the butt dyno.

 

That's the route I'll be going. Note how the iron RHS heads cost only 1/2 as much as the AFRs, And the RHS heads flow just as well through 0.400" lift on the intake side, and 0.300" on the exhaust side. With a bit of my port-n-polish magic, they should get even closer.