I've got:

4# lower
Apten ported Eaton
JL 12" filter & ram air setup
SCT flashed
FTVB
160* stat
Full weight (less trailer hitch/spare)
NGK BR7EFs
Running on stock F1s

In decent weather (79/80, light head wind), I seem to gain EXACTLY 20mph from the 1/8th to 1/4 mile.

I'm wondering if this is on-track, or should I see a little more?

 

I just checked my timeslips and yes that's about right. My mods are almost identical to yours and just about every pass it's 20mph difference from the 1/8th to the 1/4.

 

yup same here

 

Seems in line with me too. My 8.2 1/8 mile run was at 86-87 mph. That's around a 12.75 1/4 by conversion, and I saw your mph of 107 on your 12.7 run. Looks like 20 mph holds true. Incidently, that holds close to true for Top Fuel cars too. On a 315 run, they are at 275-280 at the 1/8!

BD

 

20 to 21mph here also

 

23mph here

7.88 @ 88.10
12.33 @ 111.19

 

Yes
21-23 on all the slips I just checked

 

I think if traction is not much of an issue, then 20-22mph is about right for these trucks, if you're running anywhere from 11s-13s. As you get faster (Cali mentioned Top Fuelers which see ~40mph gain), you'll see more MPH gain on the top end.

If you use nitrous, then its out the window b/c typically you will not hit it until you're into 2nd gear or whatever. It's top-end charge will be such that you will pick up more MPH out the back door.

Traction is always an issue as well. When I had my Mustang, it would run anywhere from 132-135mph in the 1/4. If I ran on slicks, I would see 103-104mph in the 1/8. If I ran drag radials, I'd be pedaling it, so I would only be going 90-92 or so (a full 10+mph less) in the 1/8th, but still run the same (or very close to it) in the 1/4 mile.

My '99 L was very lightly modded (like my '04 is now) and it would run 83 in the 1/8 and 102-103 in the 1/4 (low-13 ET).

 

Just looked at all my slips and 20 mph is the gain on almost all of them. I have almost the exact same mods as you...different tuner and plugs. Nice to know that if I had cool weather and a decent track I should be able to dip well into the 12's

My dyno numbers aren't current since I've had a dyno tune since then on a mustang dyno so with the conversion I should have around 400/490 just like you.