does anyone know how much your 0-60 would be lowered by per HP gain?

 

It would depend on the weight of the car gearing and potentially aerodynamics, in addition to altitude and barometric pressure.
Thus there is now way to be truly accurate with an "estimate"
The Net: Without a run at the dyno and then down the dragstrip it would be hard to tell-

Pet Peeve-
0-60 is a flawed test - Why do magazines continue to use this as a measuring stick?
If anything, shouldn't it be 0-65? Just curious.

I always tend to look at the 0-100 test as this is a great indicator to me of how fast the car will "probably" feel-
Many cars run super fast to 60 and then fall off hard before 100-

 

I agree with Lip.

Many car manufacturers now do whatever they can to improve
or optimize the car's 0-60 times, but it's just not that important.
Unless you are doing a brief stoplight grand prix on the street from
a stop with someone, it's pointless.

I've asked (and even written) magazines for YEARS to add two acceleration tests. Those are:

Low speed roll starting in 2nd gear...say 25-75 mph
Freeway speed roll from 75-125 mph (starting in whatever gear is best for each car).

Some mags have picked up "passing" tests but they are all from like 45-65 mph. That's not long enough to really distinguish how well the car will do for more than just a split second....but it's a start.

Some people always say, "just look at the trap speeds as an indication of how fast the car is"
Again, a good starting point and relatively true, but there are a TON of variables that will affect the trap speeds too and how the car was launched can have a BIG outcome on trap speeds.
Often the BEST ET (your time in seconds) doesn't result in your best trap speed. Why? Launching.
The better you launch the quicker you cover the 1/4 mile in time, but often the LESS time your car has to build up speed!
A crappy launch will often lead to slower TIMES, but better (faster) trap speeds, because your car had a couple split seconds longer to build up speed in the given time!