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Your opinions on this launch Gents #2794214
07/08/20 09:41 AM
07/08/20 09:41 AM
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rb446 Offline OP
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This was first time out on Sunday with new combo... 16lbs in 10x29's, 9-ways set on 5 I think, 90/10's up front, it looks to me as if its unloading tyre@around 10>15ft out, 727 4200+stall, max torque@4400, caltrac/mono's/ bottom hole with 1.5 turns preload.
your thoughts>>>.be as critical as you want. Race weight 3836lbs, 10.64@125, 1.50 60ft........https://www.youtube.com/watch?v=uA0_AmkLOWU




Last edited by rb446; 07/08/20 09:59 AM.

1969 'Cuda 446ci, best 9.96@133.9 in 1990
1971 340 'Cuda, best 11.01@122.8 in 1987
Re: Your opinions on this launch Gents [Re: rb446] #2794223
07/08/20 09:57 AM
07/08/20 09:57 AM
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No smoke on the burnout, looks like the tire was still in the wet area when the burnout ended.

You’re going to need a tripod and some slow mo.

ET/MPH and 60’ are top secret?


68 Satellite, 383 with stock 906’s, 3550lbs, 11.18@123
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Re: Your opinions on this launch Gents [Re: fast68plymouth] #2794225
07/08/20 10:00 AM
07/08/20 10:00 AM
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rb446 Offline OP
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try again, works for me.............


1969 'Cuda 446ci, best 9.96@133.9 in 1990
1971 340 'Cuda, best 11.01@122.8 in 1987
Re: Your opinions on this launch Gents [Re: fast68plymouth] #2794234
07/08/20 10:08 AM
07/08/20 10:08 AM
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rb446 Offline OP
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Originally Posted by fast68plymouth
No smoke on the burnout, looks like the tire was still in the wet area when the burnout ended.

You’re going to need a tripod and some slow mo.

ET/MPH and 60’ are top secret?


10.64@125, 1.50 60ft
Next run was a 1.50 60 and a 10.56@125.8


1969 'Cuda 446ci, best 9.96@133.9 in 1990
1971 340 'Cuda, best 11.01@122.8 in 1987
Re: Your opinions on this launch Gents [Re: rb446] #2794235
07/08/20 10:09 AM
07/08/20 10:09 AM
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fast68plymouth Offline
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What are the rear gears and finish line rpm?

Looks like the speed/ET are pretty close right now.

Gonna need to find some speed before the ET changes very much.

6E3714E3-2220-41D1-9615-557F2B9B6146.jpeg

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Dealer for Comp Cams/Indy Heads
Re: Your opinions on this launch Gents [Re: fast68plymouth] #2794236
07/08/20 10:12 AM
07/08/20 10:12 AM
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rb446 Offline OP
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Damn it I knew I forgot something..........4.10 and finish line rpm I don't know as this was his first time out with something this quick but according to wallace weight etc. etc. around 6200-ish with slip....not sure coming up on the verter works the best?...early days. and I forgot to mention there was a 30mph headwind all day...Also it was run with full exhausts on.

Last edited by rb446; 07/08/20 10:23 AM.

1969 'Cuda 446ci, best 9.96@133.9 in 1990
1971 340 'Cuda, best 11.01@122.8 in 1987
Re: Your opinions on this launch Gents [Re: rb446] #2794242
07/08/20 10:25 AM
07/08/20 10:25 AM
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What you’re interested in is what the actual rpm is.

To try and determine if it’s driving through the converter or not.

The good news is....... the same as the bad news......
None of the numbers are way off from each other.
So, the direction to go isn’t very clearly defined.

Based on that small sample of runs........ nothing stands out as an obvious “problem”.
The speed/ET/60’....... are all pretty much where they should be...... for each other.

However....... based on the current speed...... if you were trying to go .50 quicker, the car would have to show about 100hp more(7mph).

Using my bracket car “10% rule”, based on what you said the dyno numbers are....... you’re off by about 2mph.


68 Satellite, 383 with stock 906’s, 3550lbs, 11.18@123
Dealer for Comp Cams/Indy Heads
Re: Your opinions on this launch Gents [Re: rb446] #2794243
07/08/20 10:28 AM
07/08/20 10:28 AM
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What do you think is going on with body reaction etc. is what I really meant, not after exact settings as each car is different but generally how the car reacts and what would you do to calm it down is certain areas etc.etc.


1969 'Cuda 446ci, best 9.96@133.9 in 1990
1971 340 'Cuda, best 11.01@122.8 in 1987
Re: Your opinions on this launch Gents [Re: fast68plymouth] #2794245
07/08/20 10:36 AM
07/08/20 10:36 AM
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rb446 Offline OP
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Originally Posted by fast68plymouth
What you’re interested in is what the actual rpm is.

To try and determine if it’s driving through the converter or not.

The good news is....... the same as the bad news......
None of the numbers are way off from each other.
So, the direction to go isn’t very clearly defined.

Based on that small sample of runs........ nothing stands out as an obvious “problem”.
The speed/ET/60’....... are all pretty much where they should be...... for each other.

However....... based on the current speed...... if you were trying to go .50 quicker, the car would have to show about 100hp more(7mph).

Using my bracket car “10% rule”, based on what you said the dyno numbers are....... you’re off by about 2mph.


Yeah, perhaps the mph would've been a bit more without that 30mph headwind but I get what your saying, Wallace says used around 645fwhp of what it has but again thats not accurate on that day. Ioriginally worked out that the car has a best of a 10.2>3's in it@129 perhaps and we didn't touch a thing on the carb/timing or anything apart from th tyres and caltracs. I was quite please with a 10.5 on the day and a novice driver. I would prefer it to do what your car does on the hit, controlled rear and around 1ft up in the air.

Last edited by rb446; 07/08/20 10:38 AM.

1969 'Cuda 446ci, best 9.96@133.9 in 1990
1971 340 'Cuda, best 11.01@122.8 in 1987
Re: Your opinions on this launch Gents [Re: rb446] #2794246
07/08/20 10:36 AM
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Honestly....... there isn’t enough detail in the video for me make any recommendations one way or the other.

It appears to break the tires loose pretty much right at the hit to me.

Time to start playing with tire pressures and shocks.

Unfortunately, I dont think you guys get much opportunity to make passes over there.


68 Satellite, 383 with stock 906’s, 3550lbs, 11.18@123
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Re: Your opinions on this launch Gents [Re: fast68plymouth] #2794249
07/08/20 10:40 AM
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rb446 Offline OP
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Well we made 5 passes that day, first 2 were in the 11.3's as he was easy on it, could've made another 5 at least as no-one in the fire up lanes but he'd had enough, so it was 10.74@124/10.64@124.7/10.56@125.83...lots more to do, test test and test again!!

Last edited by rb446; 07/08/20 10:43 AM.

1969 'Cuda 446ci, best 9.96@133.9 in 1990
1971 340 'Cuda, best 11.01@122.8 in 1987
Re: Your opinions on this launch Gents [Re: rb446] #2794251
07/08/20 10:42 AM
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fast68plymouth Offline
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I was quite please with a 10.5 on the day and a novice driver.


I tell people all the time..... you have to start somewhere.

As you can see on the moroso chart, it shows the w/p ratio as 6.55:1 for 125.8mph, so at 3860lbs thats 589hp.

On a decent air day, my friends stocker can beat the moroso chart by over 7%(chart shows hp to be 107% of what the motor actually makes for STP power on the dyno).


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Re: Your opinions on this launch Gents [Re: fast68plymouth] #2794253
07/08/20 10:47 AM
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Which is more correct I wonder?........input 645fwhp/weight/gear/tyre size into Wallace>

Power to Weight Ratio: 5.97
60 Foot E.T. : 1.47
1/8 Mile E.T. : 6.67
1/8 Mile Trap Speed : 101.97
1/4 Mile E.T. : 10.56
1/4 Mile Trap Speed : 127
1/4 Mile Trap RPM : 6,030+


Last edited by rb446; 07/08/20 10:53 AM.

1969 'Cuda 446ci, best 9.96@133.9 in 1990
1971 340 'Cuda, best 11.01@122.8 in 1987
Re: Your opinions on this launch Gents [Re: rb446] #2794256
07/08/20 10:57 AM
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This is what Wallace shows for my friends Stocker.
Run was during class eliminations at Gainesville.
10.37@128+, 3300lbs

This motor combo has been dyno tested at least 25 times.
It has never broken the 500hp mark.

The moroso chart shows 534.8hp.

325D0C43-497F-4FC5-8E66-A2162509D2E3.png

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Dealer for Comp Cams/Indy Heads
Re: Your opinions on this launch Gents [Re: fast68plymouth] #2794258
07/08/20 11:12 AM
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A more typical amount of converter slip in that type of combo is more along the lines of 7-10%.
If the tires are “29.0”, and not “29.5” ....... the driveshaft rpm at 125.6, 4.10 gears, not accounting for tire growth is just under 6k.
With 7-10% slip I’d be looking for an engine rpm of 6400 to 6600 at the stripe.
Set the rev limiter accordingly.

If the tires are actually 29.5”, lower all rpm figures by 1.7%.


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Dealer for Comp Cams/Indy Heads
Re: Your opinions on this launch Gents [Re: fast68plymouth] #2794268
07/08/20 11:31 AM
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rb446 Offline OP
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Got it.........Were gonna get a go-pro in the car soon so we can tell whats going on, the tach he has in it is ancient, never heard of it, doubt if its any good, was showing it ticking over@500rpm in the pits, no way. So much to do in my head to get it right, and some think its easy to set a car up by just bolting stuff on. I just hope he has the thirst for ET, really all we need is consistency but to get that it has to be right. ...6400>6600 is way out of the max power band but you never know, certainly doesn't sound anything like it in the traps and it doesn't sound like its picking up rpm near the traps either, sounds a bit flat, more thought has to go into that..........Thanks for the input as always.

Last edited by rb446; 07/08/20 11:41 AM.

1969 'Cuda 446ci, best 9.96@133.9 in 1990
1971 340 'Cuda, best 11.01@122.8 in 1987
Re: Your opinions on this launch Gents [Re: rb446] #2794275
07/08/20 11:39 AM
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Yeh, a reliable..... at least “fairly accurate” tach is necessary for trying to gauge how well certain aspects of the car are working out.
Well...... unless you have a data logger.

The go-pro...... the poor man’s data logger....... Aimed at the Tac will answer some questions.


68 Satellite, 383 with stock 906’s, 3550lbs, 11.18@123
Dealer for Comp Cams/Indy Heads
Re: Your opinions on this launch Gents [Re: fast68plymouth] #2794281
07/08/20 11:43 AM
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rb446 Offline OP
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one is on its way and we gotta get a good tach/shocks front/back/carb (go better with an 850DP) and try and get him to run it on open hdrs. (worth a 1/10th?) Drove it there with exhausts, race with them, drive it home and we drove it home on the slicks, couldn't be arsed to change back over!!!........oh and the reason he wanted 16lbs in the tyres was cos he hadn't screwed them to the wheels and we turned them about 1".

Last edited by rb446; 07/08/20 11:56 AM.

1969 'Cuda 446ci, best 9.96@133.9 in 1990
1971 340 'Cuda, best 11.01@122.8 in 1987
Re: Your opinions on this launch Gents [Re: rb446] #2794305
07/08/20 12:24 PM
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6400>6600 is way out of the max power band


I realize that....... but I doubt trying to gear it for 5800-6000 is going to do anything but slow the car down.
7-10% slip in that type of combo is fairly “standard”.

The 572 in my friends Charger made peak power at 6300.
On a good day it goes thru the lights at about 7200(148mph@3660lbs).
6% slippage.

Part of the reason for the lower slippage % from his combo is the higher rpm for both the engine and driveshaft.


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Dealer for Comp Cams/Indy Heads
Re: Your opinions on this launch Gents [Re: fast68plymouth] #2794343
07/08/20 01:31 PM
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No I wouldn't do that, if it goes past dyno max power it does,....unfortunately no f/back from driver on the day which I didn't expect but it will come, just takes time to get used to the car with what it likes and get better race car parts on it whilst its still being driven as a street car on the odd occasion. Its interesting though that with the way it was set up, the weather etc. that it still ran a 10.5, and the mph wasn't quite there cos of the headwind perhaps. Lots to look forward to I think.


1969 'Cuda 446ci, best 9.96@133.9 in 1990
1971 340 'Cuda, best 11.01@122.8 in 1987
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