Desktop Dyno - Please rate this motor...


New Member
Nov 7, 2003
Cerritos, CA
Being a Mac user, I don't have access to the hord of PC software that is available. I was wondering if one of you can pass back HP and Torque estimates for this engine build?

302 Standard Bore
Stock Pistons
Boss Rods
(stockers refitted with 7/16" rod bolts)
9.5:1 Compression (estimate)
Crane 2131 Roller Cam
.050 Dur Lift
Intake 214 276 0.513
Exhaust 220 282 0.529

Dart Windsor Jr. Heads (iron)
58cc chamber
180mm runners
1.94 Intake
1.60 Exhaust
Full Roller Rockers
Edelbrock RPM Intake
Holley 670 Street Avenger Carb.
MSD Distributor
MSD Wires
Mac Long Tubes
Dynomax X-Pipe
Flowmaster Delta 50s

Motorsport T-5 Tranny
4.11 8" Posi Rear

Not sure if you need any additional information.

Thanks in advance,
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I got 346hp at 5500 through 6000rpm and the torque was 356 at 4500rpm. I based head flows at the same as my edelbrock performer RPMs since i couldnt find any flow specs for yours. What is the outlet on you headers?
using engine analyzer 3.0, i got 320hp @ 6500, 319 lb-ft @ 4500 with a production water pump, flex fan, and power steering. i added a couple hp for the MSD setup, too. i based my flow on world products windsor jr's, and i approximated the lobe separation on your cam for 110*. i also guessed at your header and exhaust CFM.
I ran a sister thread in the 5.0 forum and have five responses so far.

Average power estimate (ignoring the highes/lowest):
371 HP @ 6,167 RPM
354 TQ @ 4,833 RPM

If anyone else chimes in, I'll be able to better refine the initial estimate. After the engine is built, I do plan on getting on a dyno to measure RWHP. It will be interesting to see which program is most accurate.
66P51GT said:
Mac Long Tubes are 1 5/8" at the flange into a 2 1/2" collector.
Flow rating on the carb is 670 cfm.
Lobe center is 112*

Thanks guys,

ran it again with the new specs - found about 5 extra hp. torque band seemes a little flatter too

324hp @ 5500-6500rpm
320lb-ft @ 4700rpm
Well, that program is worth exactly what it cost. I loaded it with real head flow data and cam events from a Harley motor I did for a friend of mine last year. I have real carb flow numbers and rear whell dyno numbers. I designed the engine on Performance Trends' Engine Analyzer Pro - it predicted 135 HP at the crank. A DynoJet dyno measured 121 HP corrected at the wheel. That's an 11% loss through the drive train - very normal. The Desktop Dyno program shows less than 100 HP.

The induction flow element seems to be the weak link. Who has flow numbers at 1.5 In Hg? No matter what I put in this entry, the result never went over 100 HP.

If you want to get serious about engine modeling, go to: