What are the "advertised" duration numbers for the GMPP ZZ502 camshaft? The @.050 numbers are 224/234 with .527/.540 lift. I'd like to get a more accurate DD2000 estimate for my current engine. Entering in the numbers I do know it tells me 450hp and 550lb-ft for my 9:1 Gen VI 454 with mildly ported L29 vortec heads with the stock sized 2.07/1.72 valves.

Sorry, i couldnt find the advertised duration for that cam. Even checked the GM Performance Parts catalog. However, I believe you'll get more accurate results with the 0.050 duration numbers. There are a lot of cams with 290-300 advertised duration, but the durations at .050 can vary from 220s to 260s. Thats why i always look at the .050 numbers to see how radical the cam is.

that's why I'd like to know the intensity. Is it like 40 degrees or closer to 60? I know DD2000 is usually optimistic by 10-25% so I'm really dealing with a 340-400hp 454. Which is pretty pathetic and not really worth all of the time,money,and effort I've put into trying to shoehorn it into an s-10 Blazer. Is this engine really going to be this crappy? I'd hate to put in thousands of dollars and countless hours of work and fabrication to end up going slower than the 390hp 350 did.

May I ask why you are going to the trouble of trying to install a hy-roller when just a regular flat tappet cam will do you nicely, for a lot less money, imho...

Or is this at just the considering stage??

I guess what I am trying to say is that with no more then a regular cam, a good 454/468 motor can make 500hp and more easy!! So why bother, why not just step up to a cam like a CC 288 Street Solid Roller and be done with it....

pdq67

The engine is a '97 Vortec motor with low miles so I just reused the hydraulic rollers/ pushrods/ guideplates and then put a ZZ502 cam in there with some Harland Sharpe full roller rockers. I'm trying to get the most bang for the buck and still get into the 12's. The Blazer weighed 3200lbs with my fat ass and teh aluminum headed small block. Now with adding the 300-400lbs of cast iron to the front end and making only marginally more power it will probably be slower. I just wish I had the $8000-10000 to build a real engine so I can play with the big boys around here.

Here's the trick to DD2000. Set up a basline engine to calibrate the program - ie - set up a 454/425 HO motor using the cylinder head flow data from Chevy Hiperformance for a GM iron rec port. Set the comp at 8.75 /1 as advertised, then set the cam specs to the correct lift and play with the duration numbers until you get the correct printout. Not exact, but I think I used Int=272 / Exh=288 on 112 LSA to get it close to advertised HP & Torque. Once you calibrate the program, save the model, then use the saved model to plug in new components to validate the changes. One fault of DD2000 is it does not account for cam intensity that well.

Using the info you have given in the thread I would think 430 - 440 HP is realistic, torque should be broad at 500.

Originally posted by GRN69CHV:
...to get it close to advertised HP & Torque... I thought the OEM numbers were inaccurate themselves - more a product of satisfying advirtising than reality - have they changed?

I don't place a lot of faith in the program's accuracy, more for the generalization of finding trends. I have seen 2 different articles published on the 454/425 HO motor. Both had different reported numbers than the GM published numbers. For the purpose of DD2000, you have to calibrate the program to some known standard to get the best results. As far as establishing the advertised duration of the GM Rollers - GM doesn't give these to us {not that I am aware anyway} so we can can make some assumptions based on modern cam profiles to come up with an approximate number to use that should be close enough for the sake of setting up the program.

Try a 270/280 hy-roller for a first trial and see how you turn out, imho...

pdq67

I understand the intent and/or need to have a baseline from which to do comparisions but I certainly wouldn't refer to it as calibrating to a standard. You said yourself you have three different values for a particular engine spec - how or which value do you "standardize" on?

Given the highly variable 0.050 values between cam grinders relative comparisons may be a problem as well. Not trying to be argumentative - just pointing out that you may be having precision errors as well as accuracy errors. Without doing a lot of sensitivites we don't know what the precision issues might be or even if they are linear.

If you stay with a particular cam grinder and settle on a "standardized" value derived from several that fall in a narrow range you may be ok. At least that's how I see it. Wouldn't it be nice if the authors of software like this did sensitivities (maybe they did - I haven't read the manual they supply) and published that info?

If you are looking for a nice hyd roller for a 454, I have to make a plug for an UD HR4 (not sure what PN this is at lunati now, you'd have to ask harold. He said the grind was being updated a tad as well-- IIRC its used in a ton of mercury marine engines).
It has a big advertised duration, but has a low intensity, mean exhaust tone, nice rumble, (not sure what you're looking for here) and made for 113mph traps in a 4000lb car with a questionable converter and 3.31's. (at that point, car was 9.6:1 w/ dart alum rectangles and roller rockers, 750DP).

hth

matt

the blazer has 4.11's and will probably be riding on 28" tall ET streets and a TH350 tranny. I am just looking for a nice strong street/strip car that I can drive to work on weekdays, cruise on weekends and drive to the track on racedays. I can't have a trailor because I don't have the room. The faster the better, but I'm on a budget so I wanted to reuse the factory roller lifters and heads. I ended up blowing the budget a bit with the exhaust system costing me more than I paid for the engine.

Clarification in order here. The original post wanted to figure out how to validate the DD2000 program results. The only way I have been able to figure this out is to compare my DD2000 results against a known/published standard [which unforetunately is also had to get - I've seen the 454/425 HO reported as 425 to 437 HP]. For the sake of understanding trends on DD2000, if you plug your data in for the same motor (454/425HO) and come up with 470 HP, then something needs addressing before you start pluging in new parts or the results will be further eskew.