340 on dyno video, whats your opinion

I'm more layman than professional at this even though I own an engine dyno.

Took my A-Body 'Tetanus' to many dyno contests. Once went to a car show where they were running diesel trucks on a chassis dyno. I asked if I could run Tetanus on the dyno. The operator said, "Sure, bring it on up."

I don't remember exactly what 'ol Tetanus was making at that time but it was well over 600 RWHP. This was in, maybe 2008. On the first pull it made something like 580 RWHP. So I asked the operator, "Did you change the load on the rollers down from the diesel set-up?"

"Yeah. I took it down to a normal car setting. You won't be able to rpm at diesel load. The engine can't pull that. It will stall."

"Does 580 RWHP look like a normal car?"

"Ah, no. Do you want it back to the diesel setting?"

"Please."

Something like 640 HP was the result.

You can run at full throttle to your rpm, let's say 7,200, but not full load (torque) and the engine won't make it's potential horsepower at that rpm. It's like snapping the throttle open in neutral while sitting in your garage. Full throttle will get you to 7,200 rpm in a hurry if the engine doesn't puke itself all over the garage floor. It doesn't make much horsepower in neutral because it isn't producing much torque.

HP = TQ / 5252 X RPM. So......15 lb-ft / 5252 X 7,200 rpm = 20 HP.

Now make the same engine work, load it to say 562 lb-ft. Then we have 562 lb-ft / 5252 X 7,200 RPM = 770 HP. It will take longer to get to 7,200 rpm under load, than in the garage in neutral. Does that sound something like 300 rpm/sec vs 600 rpm/sec?

770 @ HP 7,200 rpm, is by the way, a real pull made by our pump gas 451. We actually have dozens of pulls in that range with the little 451.

300 rpm/sec holds the engine back (loads it) harder than 600 rpm/sec. If the engine has the ability to rpm at the greater load it will reveal more of the engine's horsepower.