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Cost: $550 for 9 hours and 21 pulls.


Correction: Final was 609.1 @ 5700 and 647.7 @ 4500
over 600 HP from 5200 - 5700
over 600 ft.lb. from 3700 - 5200

First run was 575/604, and every run we would change 1 thing.

On 91 octane, the engine made more power each time we took timing away. It runs best at 30° total, not the 36 I was previously running.

The carb ended up wanting 7 more sizes on the primary and one less on the secondary for a final of 84/88.

Swapping the HS air bleeds from 25 to 29 gave me about 5 on the top and got rid of a rich condition past 5000.

Adding a 1" 4 hole over a 1 inch open was worth 13 HP and 9 ft.lb. over no spacers at all.

My 14x3 paper air filter cost me 10HP over no cleaner at all, a 14x3 4 ply K&N only cost me 2HP.

There is a slight surge over 5500 that couldn't be tuned out since it is a result of not enough exhaust duration to compensate for my tiny ports. Only fixed by porting or a new cam.

Further pulls revealed the engine was still running well past 6600, but power was down to 552 out there.

I'll post copied of the dyno sheets in a little while.

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As many have stated in the past, some of these tweeks MAY or may not make the car go down the track quicker. After my chassis dyno, I needed more jet to get best et`s but hey, good numbers and good luck at the track.

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There is a slight surge over 5500 that couldn't be tuned out since it is a result of not enough exhaust duration to compensate for my tiny ports. Only fixed by porting or a new cam.

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Adding a 1" 4 hole over a 1 inch open was worth 13 HP and 9 ft.lb. over no spacers at all.

My 14x3 paper air filter cost me 10HP over no cleaner at all, a 14x3 4 ply K&N only cost me 2HP.

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Great info Were the above numbers @ peak?
Thanks.

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The surge was very audible, and the a/f ratio oscilated a fair bit. Slight variation on the otherwise smooth power curve. No intake flow data. After inspecting my cam specs we both agreed on the lack of exhaust duration. Some tunes had a more or less pronounced effect, but it was never gone.

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Thanks all,

The surge was very audible, and the a/f ratio oscilated a fair bit. Slight variation on the otherwise smooth power curve. No intake flow data. After inspecting my cam specs we both agreed on the lack of exhaust duration. Some tunes had a more or less pronounced effect, but it was never gone.

As a rule we shot for the best averages between 4100 and 6200, which happened to be the same run as the best peaks. Some changes did give better peaks than previous runs but losses on the averages.

My scanner is on the fritz, so the result sheets will have to wait until this evening.

On the whole, I am very happy with the results.

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Nice job.... could you change the RPM of the surge
or did it start at the same point each run(even with
added fuel.... if you couldnt change the rpm I would
think valve train also

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Adding a 1" 4 hole over a 1 inch open was worth 13 HP and 9 ft.lb. over no spacers at all.

My 14x3 paper air filter cost me 10HP over no cleaner at all, a 14x3 4 ply K&N only cost me 2HP.

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Great info Were the above numbers @ peak?
Thanks.

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The surge was very audible, and the a/f ratio oscilated a fair bit. Slight variation on the otherwise smooth power curve. No intake flow data. After inspecting my cam specs we both agreed on the lack of exhaust duration. Some tunes had a more or less pronounced effect, but it was never gone.

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Not being there, this is kind of a s.w.a.g., but that sounds more like you got into valve train instability from about 5500 on up, not an indication of insufficient exhaust duration.

It looks like you're running some fairly aggressive solid flat-tappet lobes and those things will start to act up at high(er) RPM w/o a fairly stiff spring load. What sort of springs do you have and what are they set up for closed & open pressures?

I don't know if you can make the same interpetation from A/F ratio fluctuation, but when the measured air flow #s start showing fluctuations above a certain RPM, that can be a sign of the valve train losing control.

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67Charger:

440 +.040, stroked to 496 with a 440source 4.15 kit
10.44:1 compression, 91 octane pump gas
Holley 1000HP
MP M1 single plane intake
.597/.607 257°/259° @.050 solid flat tappet
Eddie RPM heads, unported, port machining transitions smoothed/gasket matched
2 1/8"/3.5" TTI headers
MP distributor, 35° total

Final was 609.1 @ 5700 and 647.7 @ 4500
- over 600 HP from 5200 - 5700
- over 600 ft.lb. from 3700 - 5200

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Nice results.

- What is the lobe separation on that cam?
- Is the cam installed advanced?