71 Duster Dyno

When working from the chassis power numbers you need to divide by the (1 minus power loss) estimate.
For instance, if you believe the chassis loss is 18%, then you would divide the net power by (1 less 18%). so that would be 356/(1 - .18 ) = 356/.82 = 434 crank hp.
To double check this, subtract the .18% from 434
That would look like 434 x (1- 18%) and that simplifies to 434 x .84 = 356! The actual power loss to the chassis would then be 434 - 356 = 78hp
This seems excessive, considering that the Hughes very similar engine, cranked out 437/437. What I'm suggesting, is that there's still something left in her,to be found in the tune, and the mph seems to bear this out.
The Duster at say;3400 race weight and 434 crank hp maths out to;3400/434 = 7.83 P/W. With a stick car this should go about 119mph and with an unlimited chassis this might go 11.2seconds. A street chassis might add a second or more so I guess 12.2 to maybe 12.5.
Op's (Greg's)109mph, says the engine is lazy(or short shifted,etc), while the 13.4 ET says the chassis is lazy.
At 109, the bulletin #40 says the engine is pulling just 10.0 P/W, which at 3400lbs is just 340 crank hp.
Shifting at peak horsepower,instead of centering the shifts around the power curve,could be a part of that.
With the A833 having spits of 73%, meaning that the revs drop to 73% at the shift,,shifting at 5600(my estimation of where the Peak is) would drop the Rs to 4100, and that is not gonna make for a good ET. The average Hp for a 4 gear run will thus be in the basement.
So what is needed is to rev well past the peak, to keep the average HP up. With the A833, this might work out to 6300. Shifting at 6300 dropping to 73% is about 4600. This puts the peak dead center at 5600, and the average hp up,a fair amount.
Looking at the dyno chart, it is impossible to know at what engine rpm stuff is happening. If we knew the rear gear and tire size, we could recalculate, and convert roadspeed to rpm, and then a better shift rpm could be determined. I just kindof guessed, based on my engine's preference.
So once the correct shift rpm has been selected and worked out with shift- loops, then timing and jetting, will optimize the engine combo. From there the MPH will settle down. Then you get to mess with the chassis.
I was happy with 93 in the eighth, so,for me,chassis be hanged.I don't care if it ain't that quick. I built it as a DD, and need a decent ride.Besides, it's kindof fun to be able to spin 295s anywhere,anytime.....