505 dyno test results

If the throttle wasn’t released before the end of the pull, then I’d say something got unhappy.
(Loses 69ft/lbs in 177rpm)

Perhaps looking at some of the sheets from other pulls might show a trend.

Dyno story #2-
I had ported and set up some heads and got a cam for a customer.
They had the motor on a dyno local to them, and the power was really falling off pretty quick at the end.
And the repeatability of the upper rpm numbers was pretty poor.
He called me, we talked about it a bit.
I was pretty confident the springs were enough to go higher than what they were turning the motor, but conceded more spring was probably a good place to start.
So they got replaced with something that were about 100lbs more open pressure.
No difference.

The dyno I use here is a SF-901.
With their operating system, the computer will end the pull for you at the predetermined upper rpm limit.
You don’t need to anticipate it…….. keep the handle at WOT until you hear the motor get more load at the end, then let off.
The shop where this engine was being tested had the same kind of dyno…….. but……the operator was anticipating the end of the pull and was rolling out of the throttle early.

Just an “fyi”…….. the fuel flow, and with that……. The bsfc numbers on that sheet aren’t correct.