It's about 13.7 or so at the tip of the tail pipe. At the header, this would be about 13.3.

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Josh, this is about what I've heard. I know of .5 less at the header.

TFS ~2000 foot DA

1.814 (TFS by .135)
5.176 (TFS by .08)
7.885 @ 89.43 (TFS by .04 / AFR by .84 MPH)
12.115 @ 119.34 (AFR by .003 / TFS by 1.21 MPH)

AFR ~1500 foot DA

60' - 1.949
330' - 5.256
1/8 - 7.925 @ 90.27
1/4 - 12.112 @ 118.13

You can see that even though I botched the 60' time, the AFR heads are gaining ground on the TFS heads almost all the way down the track, and they did out ET the other heads by a small margin, which is impressive since I was so much slower in the first 60'.

The thing that is troubling me the most is that the the car with the TFS heads on it would pretty routinely pick up 29-30 MPH from the 1/8 to the 1/4. Now, with the AFR heads, last night all it would pick up was 28 MPH, and was as low as 26 on a couple passes.

I had the same 150 lb. passenger that I had last time. I made one pass without the passenger, but I'm not a consistent enough driver to realize the benefits of losing 150 lbs. in just making a single pass.

Traction isn't an issue. I run 16 inch bias ply ET streets, and they dead hook every time. The thing that kills my short times is the motor bogs down after I launch. I haven't spent as much time in the car as I should, and the finesse of slipping the clutch slightly to effectively launch the car isn't something that I'm gifted at. I am basically dropping the clutch at about 4K, the car lurches forward, bogs, and then I continue the pass. I was getting better at it with the TFS heads (as you can see by the better short times) but it's been awhile since I've been to the strip, so I'm a little rusty. I was also there by myself, no support vehicle, no trailer, nothing... 80 miles from home. If I broke, I was in trouble so that was in the back of my mind every time I staged the car.

I think with some tuning tweaks I can work the bog out of the motor on the launch. The other C4's that I've driven don't have this problem, but they have all been MAF cars as opposed to my speed density. For example, Jonescap has a 96 LT4, 6 speed car. I have made one pass in his car at the strip. On 17 inch nittos, I went 1.76. First time ever in his car. The fastest my car has ever gone, on bias ply slicks, with nitrous, is 1.74. I went nearly as fast as my best ever, with less tire, on my FIRST trip down the track in his car. With some careful tuning of the timing and fuel tables, I think I can get the car to leave better, but I haven't really explored it yet. For testing purposes, it wouldn't be fair to do that now because I didn't do it with the TFS heads. However, now that the testing is over, I will probably pursue it.

Regardless, I am little disappointed with the MPH, but I'm not willing to get too worked up about it until I hit the track again and have a greater sample size from which to draw an opinion.

In the end though, I was hoping for more this track trip.

For anyone who reads this far, final ET and MPH for the AFR heads after getting some seat time is 11.37 @ 122.

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FWIW
Your TFS heads on my near identical 383 w/847 cam (234/242 540/560) made 410 RWHP
Given I ran 12.1 with stock TFS 195's and a ZZ409 cam (226/520 ) expect to well into the 11's
once I have fixed the broken trans.