Originally Posted by smurf stang
So olerodder you dyno'ed you car and it laid down 686 but you yanked the motor and on the stand it only put out 658? Never seen that before unless there was a problem somewhere along the lines.
I know numbers can be flubbed but that is a huge difference.
Sorry, I've been out of town.
When I did the refresh on my 408 we put it on Dinan Motor Sports of Morgan Hill engine dyno for break-in and tuning we got 642hp@6800rpm and 544lbft@5700rpm. Also wanted to see where max torque was so Mike @ Mike's Transmission of Lancaster, CA could put a loose converter together for me. We did 12 pulls and the last one was 658hp@6800 and 550@5800rpm. After I got the motor in the car I went to the oldest hot rod shop in Northern California
...can't remember the name as they've gone out of business and put it on their chassis dyno....they got 686hp the first pull...I told them to stop as their dyno couldn't be correct...anyway I left. I also went to another shop in Northern Cal where it produced 668hp at the rear wheels....I just figured that guy didn't know his head from a hole in the ground.
Chassis dyno's are not accurate at all...IMHO