Secondary diaphram/flap opening time

[garybohannon]

What would be a good time span for a vacuum diaphram to open on a low 12 second, 3900 lb, 455 with a 3500 stall and 3.42 rear gear? Mine is about 2.5 seconds.
My friends 79 Trans Am slams the tires hard with a 1 second diaphram and his car runs about 13 flat with a 403, 3200 stall 3.23 gear at 3900 lb. It feels like a bus plowed into the back of the car when it launches. This is on the street! Unreal!
1 second seems too fast, but what have you guys done with your cars?
If I order a modified one from Cliff, I want to get it right.

[Cliff Ruggles]

1 to 1.5 seconds for your application. You just need enough delay in the pull-off to avoid a momentary lean condition when going to full throttle with good traction.  The airdoor spring adjustment will cover the rest of the deal.....Cliff