So, I took my car to the strip for the 1st time. It has a fresh 505 big block that was dyno’ed at 536 hp, 5400 rpm (flywheel hp, open headers). I am trying to estimate how “happy” the dyno was:

The car:
1969 road runner
fiberglass hood
no front bumper
aluminum heads, intake, master cylinder
about 30 lbs of hushmat
about 30 lbs of torque boxes, frame connectors
I would guess 3800 lbs with driver
3.23 no sure grip
4 speed
power steering
normal 7 blade fan, no clutch
headers but otherwise full exhaust

Weather was hot, maybe 85F, 60% RH

My runs:
13.46 @103.3 - 2.31 60’ - missed 3rd and shut down a little early
14.38 @108.4 – 2.91 60’ – spun badly off the line
13.52 @109.9 – 2.47 60’ – no major incidents

I was out launched badly every time, probably because of driver and traction issues.

Thanks!

I estimated 3850 w/ driver, since I actually think people underestimate their weights/fuel/etc....

BUT, given you're trap speeds, I'd say right around 400hp to the rear wheels.

Broken parts are probably in your future, especially if you put slicks on. 505 + 4 speed + open diff

I'm guessing your race weight at closer to 3900. Based on your MPH you should be at 394 at the rearwheels.

Well, when I used the calculator, I got 393 rwhp. However, plugging that into the et calculator gives 12.4 ET (vs 13.5 that it ran). So I obviously am not getting all of the power to the ground.

Assuming I somehow got it to run 12.4, I would have to think my trap speed would go up maybe 2-3 mph, so more hp by the calculator.

I think that maybe the final number would settle in around low to mid 400's after iterating between the ET and trap speed calculators, which isn't far from what the dyno got.

Or am I in denial??

No calculator help, just guessing: @ 109+ in 3800 lbs through a 4-speed, I'm guessing you're making just shy of 500 horsepower at the motor. But the early stuff is killing you for sure. By comparison, My Satellite goes 12.20's at 112, and I figure I'm right at 500 HP with the car weighing in at 3775.

Get ready,...... here comes the sickness!

The Moroso Speed Calculator puts you at about 395 net actual flywheel hp.

I would focus on getting a sure grip, maybe a better tire, track launching/driving/shifting practice and tuning before I would get to excited about what the HP is based on your one outing.

I bet you'll be in the low 12s @ 115 mph with a 1.9 sixty ft in no time.

The way your MPH is jumping all over the place its hard to say, I'm sure theres another 5 MPH or more in it, so lets say 114, thats in the 11s, your gears are hurting you, I see this alot but don't understand, why do guys build a somewhat monster style engine only to kill it with highway gears , if you want a cruiser, put a mild 318 in it!!