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Re: Big Block Max RPM [Re: rebel] #2703328
10/03/19 07:06 AM
10/03/19 07:06 AM
Joined: Mar 2003
Posts: 2,073
PA
moparacer Offline
top fuel
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Factory B block 499 here. Shift at 6800 and cross at 7100 with Indy -1's.


67 Barracuda street/bracket car 11.27-119
68 Dart 502 BB 8.70s-152
414 cid SB Dragster 7.65-174
Re: Big Block Max RPM [Re: fast68plymouth] #2703342
10/03/19 08:42 AM
10/03/19 08:42 AM
Joined: Jan 2003
Posts: 8,968
Frostbitefalls MN (Rocky&Bullw...
gregsdart Offline
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Frostbitefalls MN (Rocky&Bullw...
Originally Posted by fast68plymouth
.750 lift roller cam with a 1.5 rocker.

Cams with that much lift using 1.5 rockers usually have quite a bit of duration.
Any other cam specs you can share?

I’d get a few more laps on it, hopefully at wot for the entire 1/4 mile, before I thought about changing anything significant.

Along with that it would be a good idea to go over every possible rpm limiting problem that might exist. Start with valve springs. How much seat pressure and over the nose pressure do you have, and does it match the lobe profile you have? Fuel delivery OK? Ignition good enough? Sometimes rev limiters start dropping cylinders too early for the rpm selected. A 500 inch 440-1 headed motor with a .750 lift 1.5 rocker setup would have at least 276 @ .050 intake duration and probably more like 282+! With a well sorted out motor i would expext power to peak at 7,000 to 7200 rpm with torque peaking about 5400. It should easily pull to 7200 or a bit more.


8.77 153 mph best, 3055 lbs 528 indy 440-1 alky
Re: Big Block Max RPM [Re: gregsdart] #2703443
10/03/19 02:16 PM
10/03/19 02:16 PM
Joined: Aug 2011
Posts: 49
San Diego, USA
SoCalRacer Offline
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San Diego, USA
Two things:
1. You really need to get some full throttle quarter mile passes, as finish line mph and rpm will tell you a lot. For example you’ll be able to calculate the correct rear gearing. Comparing ET and mph you’ll be able to compute converter slippage. Without knowing these numbers any converter or gear changes are a crapshoot. Also, running high rpm “just because you can” is not really what you want to do. The dyno sheet tells you what you need to know. Shifting a couple/few hundred past peak power will likely yield the best performance, so spinning it to the moon won’t help unless you have a very flat power curve and it allows your rpm after each shift to fall back into a favorable power range.
2. As others have said, the 60’ is way off. My old car would 60’ around 1.47 and it was an 11.0’s car (also an E-Body at 3,200 lbs. race weight, small block). Right after getting some baseline full throttle runs this needs to be the number one thing to focus on.
3. OK, make it three things. Rather than changing rear gear, go to a taller tire. If you can borrow a set of 14x32 would be a good test to see if that’s the direction you need to go.

Last edited by SoCalRacer; 10/03/19 02:21 PM.

If it ain't broke ... you're not pushing it hard enough.
Re: Big Block Max RPM [Re: SoCalRacer] #2703569
10/03/19 06:52 PM
10/03/19 06:52 PM
Joined: Dec 2018
Posts: 51
MASSACHUSETTS
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Chip Offline OP
member
Chip  Offline OP
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MASSACHUSETTS
Thanks for the help guys...

I put a few more passes this weekend on the Barracuda.

R/T......067
60'.....1.499
330'...4.183
1/8.....6.436>>>MPH 108.68
1000'...8.391
1320'...ET 10.147 @ 120.29 MPH (I lifted early or 1320 would be better)

AND...

R/T......062
60'.....1.527
330'...4.233
1/8.....6.504>>>MPH 107.32
1000'...8.477
1320'...ET 10.158 @ 131.91 MPH

AND...

R/T......045
60'.....1.438
330'...4.120
1/8.....6.415>>>MPH 106.98
1000'...8.451
1320'...ET 10.197 @ 129.08 MPH


Had about 7000-7200 RPM thru the 1/4 finish

I will go test and tune the weekend of the 13th to gather more info. My friend thinks a tighter converter may help...he said 200-rpm tighter.

I'm a rookie driver...but getting better with 15 passes total.

So much fun!

Re: Big Block Max RPM [Re: Chip] #2703573
10/03/19 06:58 PM
10/03/19 06:58 PM
Joined: Feb 2005
Posts: 16,312
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pittsburghracer Offline
"Little"John
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Posts: 16,312
PA.
Originally Posted by Chip
Thanks for the help guys...

I put a few more passes this weekend on the Barracuda.

R/T......067
60'.....1.499
330'...4.183
1/8.....6.436>>>MPH 108.68
1000'...8.391
1320'...ET 10.147 @ 120.29 MPH (I lifted early or 1320 would be better)

AND...

R/T......062
60'.....1.527
330'...4.233
1/8.....6.504>>>MPH 107.32
1000'...8.477
1320'...ET 10.158 @ 131.91 MPH

AND...

R/T......045
60'.....1.438
330'...4.120
1/8.....6.415>>>MPH 106.98
1000'...8.451
1320'...ET 10.197 @ 129.08 MPH


Had about 7000-7200 RPM thru the 1/4 finish

I will go test and tune the weekend of the 13th to gather more info. My friend thinks a tighter converter may help...he said 200-rpm tighter.

I'm a rookie driver...but getting better with 15 passes total.

So much fun!




Now that looks more like it. I’ll bet that 60 foot time felt much better to you. I like it when it hurts my old bones a little. Congratulations and go out ant track tune before sending your convertor out to get some more info and tighten up those 60 foot times.


1970 Duster
Edelbrock headed 408
6.143@110.85 mph
9.73@135.05 mph shifting at 6700 RPM
422 Indy headed small block
5.982@112.56 mph
9.42@138.27

Livin and lovin life one day at a time




Re: Big Block Max RPM [Re: Chip] #2703625
10/03/19 09:45 PM
10/03/19 09:45 PM
Joined: Aug 2003
Posts: 35,914
Bend,OR USA
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Cab_Burge Offline
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Posts: 35,914
Bend,OR USA
What RPM are you shifting it at and what RPM is it crossing over the finish line at?
Are you foot stalling it or is it on a trans brake? What RPM are you leaving the starting line at also?
Your reaction times are consistent bow The little ET change makes me think it was getting warmer outside air temps or higher density altitude between runs, correct?


Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)
Re: Big Block Max RPM [Re: pittsburghracer] #2703628
10/03/19 09:47 PM
10/03/19 09:47 PM
Joined: Aug 2003
Posts: 35,914
Bend,OR USA
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Cab_Burge Offline
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Bend,OR USA



Now that looks more like it. I’ll bet that 60 foot time felt much better to you. I like it when it hurts my old bones a little. Congratulations and go out ant track tune before sending your convertor out to get some more info and tighten up those 60 foot times. [/quote]
I got tired of my cars hurting my neck and back so I learn to stiffen up my neck and push myself way back into the seat before hitting it hard on the starting line up scope

Last edited by Cab_Burge; 10/03/19 09:48 PM.

Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)
Re: Big Block Max RPM [Re: Cab_Burge] #2703645
10/03/19 11:59 PM
10/03/19 11:59 PM
Joined: Jan 2003
Posts: 27,389
Balt. Md
3
383man Offline
Too Many Posts
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Balt. Md
That's more like it should run. Glad to see you got it working good. That 1.43 sixty is more in line but I bet you still have more in it. Nice improvement. up Ron

Re: Big Block Max RPM [Re: 383man] #2703684
10/04/19 03:37 AM
10/04/19 03:37 AM
Joined: Oct 2015
Posts: 416
UK
rb446 Offline
mopar
rb446  Offline
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Joined: Oct 2015
Posts: 416
UK
Following this thread, its good your having fun and thats much better, but if your really making 766hp with your weight/tyre/gearing and a good working converter your ticket would look like this>

Power to Weight Ratio: 4.11
60 Foot E.T. : 1.30
1/8 Mile E.T. : 5.89
1/8 Mile Trap Speed : 115.43
1/4 Mile E.T. : 9.33
1/4 Mile Trap Speed : 144
1/4 Mile Trap RPM : 6,697 +slip


As to your current new time slips, it seems that you could have around 16% verter slip and are only able to use 590fwhp from the motor>

60 Foot E.T. : 1.42
1/8 Mile E.T. : 6.42
1/8 Mile Trap Speed : 105.82
1/4 Mile E.T. : 10.18
1/4 Mile Trap Speed : 132
1/4 Mile Trap RPM : 6,139+16% slip=7121rpm.

Just a few calcs I did that may explain it some, I could be wrong?...I'm sure you'll get it sorted.


1969 'Cuda 446ci, best 9.96@133.9 in 1990
1971 340 'Cuda, best 11.01@122.8 in 1987
Re: Big Block Max RPM [Re: Chip] #2703694
10/04/19 05:43 AM
10/04/19 05:43 AM
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Posts: 8,735
MN
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JERICOGTX Offline
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MN
Originally Posted by Chip
My friend thinks a tighter converter may help...he said 200-rpm tighter.



As has been said before, you need a more efficient convertor, not a tighter one.


69 GTX 68 Road Runner
Re: Big Block Max RPM [Re: rb446] #2703696
10/04/19 05:53 AM
10/04/19 05:53 AM
Joined: Jan 2003
Posts: 8,968
Frostbitefalls MN (Rocky&Bullw...
gregsdart Offline
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Frostbitefalls MN (Rocky&Bullw...
Originally Posted by rb446
Following this thread, its good your having fun and thats much better, but if your really making 766hp with your weight/tyre/gearing and a good working converter your ticket would look like this>

Power to Weight Ratio: 4.11
60 Foot E.T. : 1.30
1/8 Mile E.T. : 5.89
1/8 Mile Trap Speed : 115.43
1/4 Mile E.T. : 9.33
1/4 Mile Trap Speed : 144
1/4 Mile Trap RPM : 6,697 +slip


As to your current new time slips, it seems that you could have around 16% verter slip and are only able to use 590fwhp from the motor>

60 Foot E.T. : 1.42
1/8 Mile E.T. : 6.42
1/8 Mile Trap Speed : 105.82
1/4 Mile E.T. : 10.18
1/4 Mile Trap Speed : 132
1/4 Mile Trap RPM : 6,139+16% slip=7121rpm.

Just a few calcs I did that may explain it some, I could be wrong?...I'm sure you'll get it sorted.

I agree. Unless you are racing at 8500 ft, your times are off the mark. What is your location, and what was the weather?


8.77 153 mph best, 3055 lbs 528 indy 440-1 alky
Re: Big Block Max RPM [Re: gregsdart] #2703819
10/04/19 12:52 PM
10/04/19 12:52 PM
Joined: Jan 2003
Posts: 13,295
So. Burlington, Vt.
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fast68plymouth Offline
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Posts: 13,295
So. Burlington, Vt.
I wouldn’t change anything until you get some more laps on it.

Try and get into a routine, and a set-up where you get the 60’ times to repeat closer than what you’re currently getting.

Concentrate on keeping the shift points consistent, and make sure you’re not letting off until past the finish line.


68 Satellite, 383 with stock 906’s, 3550lbs, 11.18@123
Dealer for Comp Cams/Indy Heads
Re: Big Block Max RPM [Re: Chip] #2703822
10/04/19 12:57 PM
10/04/19 12:57 PM
Joined: Aug 2003
Posts: 35,914
Bend,OR USA
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Cab_Burge Offline
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Posts: 35,914
Bend,OR USA
Originally Posted by Chip
Thanks for the help guys...

I put a few more passes this weekend on the Barracuda.

R/T......067
60'.....1.499
330'...4.183
1/8.....6.436>>>MPH 108.68
1000'...8.391
1320'...ET 10.147 @ 120.29 MPH (I lifted early or 1320 would be better)

AND...

R/T......062
60'.....1.527
330'...4.233
1/8.....6.504>>>MPH 107.32
1000'...8.477
1320'...ET 10.158 @ 131.91 MPH

AND...

R/T......045
60'.....1.438
330'...4.120
1/8.....6.415>>>MPH 106.98
1000'...8.451
1320'...ET 10.197 @ 129.08 MPH


Had about 7000-7200 RPM thru the 1/4 finish

I will go test and tune the weekend of the 13th to gather more info. My friend thinks a tighter converter may help...he said 200-rpm tighter.

I'm a rookie driver...but getting better with 15 passes total.

So much fun!

Looking at all three time slips and keeping in mind about your lifting early on the first pass and then looking at the third pass 60 Ft. times with a loss of MPH and ET in the 1/4 mile but a lot quicker ET in the 60 ft. times and quicker in the 1/8 mile with a small loss of MPH makes me think maybe you have a fuel delivery problem now work twocents

Last edited by Cab_Burge; 10/04/19 12:59 PM.

Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)
Re: Big Block Max RPM [Re: Chip] #2704032
10/05/19 07:49 AM
10/05/19 07:49 AM
Joined: Jan 2004
Posts: 627
IL
D
Dart451 Offline
mopar
Dart451  Offline
mopar
D

Joined: Jan 2004
Posts: 627
IL
Originally Posted by Chip
Thanks for the help guys...

I put a few more passes this weekend on the Barracuda.

R/T......067
60'.....1.499
330'...4.183
1/8.....6.436>>>MPH 108.68
1000'...8.391
1320'...ET 10.147 @ 120.29 MPH (I lifted early or 1320 would be better)

AND...

R/T......062
60'.....1.527
330'...4.233
1/8.....6.504>>>MPH 107.32
1000'...8.477
1320'...ET 10.158 @ 131.91 MPH

AND...

R/T......045
60'.....1.438
330'...4.120
1/8.....6.415>>>MPH 106.98
1000'...8.451
1320'...ET 10.197 @ 129.08 MPH


Had about 7000-7200 RPM thru the 1/4 finish

I will go test and tune the weekend of the 13th to gather more info. My friend thinks a tighter converter may help...he said 200-rpm tighter.

I'm a rookie driver...but getting better with 15 passes total.

So much fun!







Read what Monte says about stadard hygard and tightening the converter.

I have been using low viscosity with good results

hygard jd fluid

Last edited by Dart451; 10/05/19 07:50 AM.
Re: Big Block Max RPM [Re: Dart451] #2704054
10/05/19 09:14 AM
10/05/19 09:14 AM
Joined: Sep 2003
Posts: 342
montana
BANDIT Offline
enthusiast
BANDIT  Offline
enthusiast

Joined: Sep 2003
Posts: 342
montana
Looking at the inconsistency in the short times, “rookie driver”, and footbrake, I would get a buddy to film a few passes to see what chassis and tires are doing. Then maybe put a more experienced driver in for a few passes. As stated above, you need more laps and understanding on what car and driver are doing before doing any big changes. Foot braking and consistent launch rpm were always a challenge for me without a 2 step, not sure what you are using. Main thing tho, keep having fun.


64 Dodge Coronet 440. In progress
1998. Dodge Avenger. 8.50@162. 4900 DA
250” Neil and Parks Slip Joint. 7.36@183.
4600 DA
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