Desktop Dyno Help

[68camaro396]

Hey guys, I was fooling around on Desktop Dyno 2000 today. I put together a little combo for my BBC 396 (402=.30 over) Here is a pic, the HP is pretty high up, how would i bring it down and get it closer to the torque curve. Basically what should I change to refine this set up? Note-- I didn't know the specs on the comp cams cam I used, so I found a sample spec sheet with some numbers on it and plugged those in at the bottom. Thanks for any help.

[OHCbird]

1. Bump the compression up- it'll be fine with 9.5 and those heads. I'm assuming pump gas...

2. Run a wider LSA, to the tune of 110-112, with more lift. Look for something in the .550" range (with stock 1.75 rockers).

3. Spec out a HP 830 carb. DD doesn't have the ability to plug & play different booster or jet combos, but the 750 won't offer you the responsiveness of an 830/850. Hell- I've got a buddy that has an Edelbrock Qjet copy on a 402 that runs real nice.

4. Even though DD will show different peak power #s, the performer RPM does real well on street 402s.

A real good dyno tune will put the power where it needs to be.

[68camaro396]

Hey I'll try that. Thanks for the help. I didn't even notice that it was at 8:1 compression....STUPID ME

Thanks again

[Zee]

Change over to a dual plane manifold. Also the CFM is not the carb CFM but the CFM of the entire intake system including air cleaner. Perfomer RPM is probably flowing around 96-97% of carb cfm. I don't know what affect the cleaner might have.

The user manual says your primary's ID needs to be 105-125% of the exhaust valve to use the large tube headers so I would think you would need 2" primaries to use that selection from the drop down. 1 3/4 - 1 7/8" woulld likely run better anyway.

You will probably need to include an overbore in the bore dimensions.

Finally, your lift specs look very low for a roller. If the specs are correct, then I doubt the roller selection would be very realistic and you should be using one of the flat tappet drop downs. Go into the cam math and play around with advancing the cam.

[68camaro396]

Hey I changed some things the way you guys suggested. How does this look?

Thanks again for the help.

[trackrat79]

Could I get you to plug some numbers in for me and see were i am at. I would like to get DD but don't have my own computer to put it on.

[68camaro396]

No problem. I'll do my best. I am still learning the software. Just leave me the numbers.

Be as specific as possible, since this version doesn't have all that many options for combos.