Moparts

Big Block Max RPM

Posted By: Chip

Big Block Max RPM - 09/24/19 10:47 AM

First race weekend eva at 58 years old in my 1970 Barracuda with a 440 stroked to 500-inch...check mark in the bucket list cool

Ran a best 10.72 but was letting up...testing, newbe, and car was hitting the rev limit. I had a 7000 module limit in my MSD 7AL-3.

Car weighs 3150 with me in it, has a 430 Dana rear, 3 speed 727, 31x15 big tire...i know there is more in it. Max torque 653 @ 5500-rpm and max hp 766 @ 6600rpm

How high to you guys rev your big blocks?
Posted By: n20mstr

Re: Big Block Max RPM - 09/24/19 11:53 AM

Originally Posted by Chip
First race weekend eva at 58 years old in my 1970 Barracuda with a 440 stroked to 500-inch...check mark in the bucket list cool

Ran a best 10.72 but was letting up...testing, newbe, and car was hitting the rev limit. I had a 7000 module limit in my MSD 7AL-3.

Car weighs 3150 with me in it, has a 430 Dana rear, 3 speed 727, 31x15 big tire...i know there is more in it. Max torque 653 @ 5500-rpm and max hp 766 @ 6600rpm

How high to you guys rev your big blocks?


It really depends on what head is on your engine. However, if you made 766 @ 6600, id bet shifting at 6800-7000 and going thru the stripe at 7000 would work well. You may want to re think your gearing. 3.70? might work better.
Any case if you made your most power at 6600, going much past it is not going to help, even if the engine has light weight components that can rpm higher.(steel or alum rod)
Posted By: an8sec70cuda

Re: Big Block Max RPM - 09/24/19 12:20 PM

Originally Posted by n20mstr
Originally Posted by Chip
First race weekend eva at 58 years old in my 1970 Barracuda with a 440 stroked to 500-inch...check mark in the bucket list cool

Ran a best 10.72 but was letting up...testing, newbe, and car was hitting the rev limit. I had a 7000 module limit in my MSD 7AL-3.

Car weighs 3150 with me in it, has a 430 Dana rear, 3 speed 727, 31x15 big tire...i know there is more in it. Max torque 653 @ 5500-rpm and max hp 766 @ 6600rpm

How high to you guys rev your big blocks?


It really depends on what head is on your engine. However, if you made 766 @ 6600, id bet shifting at 6800-7000 and going thru the stripe at 7000 would work well. You may want to re think your gearing. 3.70? might work better.
Any case if you made your most power at 6600, going much past it is not going to help, even if the engine has light weight components that can rpm higher.(steel or alum rod)

iagree
Posted By: Chip

Re: Big Block Max RPM - 09/24/19 01:10 PM

Indy 440-1 Heads Ported at Brandywine with 750 lift roller cam 1.5 ratio T&D rockers
Posted By: fast68plymouth

Re: Big Block Max RPM - 09/24/19 01:11 PM

766hp@3150lbs.......
Assuming a 10-12% loss for atmospheric conditions and parasitic losses....... 675-690hp.
Should be good for about 140-141mph.
Assuming the typical 10% converter slip, 4.10’s would put you in the 7000rpm range.

That isn’t a problem as long as the valvetrain is set up for that, along with the oil system.

4.30’s seems like it would be a bit too much gear if everything is working as it should.
Posted By: bigdad

Re: Big Block Max RPM - 09/24/19 02:28 PM

My 470

I shift it at 6500 , runs thu the lights at 6500

tires are 14x31 Goodyears, gears at 4.30's

last weekend , it did nice wheelstand , short time was 1.38 4 -- ran 10.49 @ 124.8

me in car it weighs 3280 full of fuel
Posted By: JERICOGTX

Re: Big Block Max RPM - 09/24/19 02:51 PM

I think you need a new convertor. should not be going through the traps at that high of RPM, with those gears.
Posted By: bigdad

Re: Big Block Max RPM - 09/24/19 02:52 PM

those tires roll out at 97 inches, they are short ..going to put taller ones on next year
Posted By: dvw

Re: Big Block Max RPM - 09/24/19 03:06 PM

I run 10.5x31 with a 4.30. 7100@145mph. Your converter is slipping way to much. At 10.70s you're a what? 124 mph?
Doug
Posted By: pittsburghracer

Re: Big Block Max RPM - 09/24/19 03:07 PM

Originally Posted by Chip
First race weekend eva at 58 years old in my 1970 Barracuda with a 440 stroked to 500-inch...check mark in the bucket list cool

Ran a best 10.72 but was letting up...testing, newbe, and car was hitting the rev limit. I had a 7000 module limit in my MSD 7AL-3.

Car weighs 3150 with me in it, has a 430 Dana rear, 3 speed 727, 31x15 big tire...i know there is more in it. Max torque 653 @ 5500-rpm and max hp 766 @ 6600rpm

How high to you guys rev your big blocks?





What was your mph on the 10.72 pass


What was the 60 foot and 1/8 mile times.
Posted By: Chip

Re: Big Block Max RPM - 09/24/19 04:43 PM

R/T .117

60 ft 1.539

330' at 4.274

1/8 at 6.658 at 103.35 MPH

1/4 at 10.723 at 109.48 MPH (but i was letting off)... My dial in was 10.75

Probably need a tighter converter...
Posted By: dvw

Re: Big Block Max RPM - 09/24/19 05:00 PM

Not tighter. More efficient. All the progressive numbers are way off. What converter is in it? At that power level and weight you should be 9.60 or better.
Doug
Posted By: DusterKid

Re: Big Block Max RPM - 09/24/19 05:13 PM

Was the car hooking? My car had a 1.53 60' when I went 11.50s...For the power your making your 60' should be 1.3x something I'd think.
Posted By: n20mstr

Re: Big Block Max RPM - 09/24/19 05:17 PM

I would be calling Ultimate, or PTC, or ATI, or some other reputable converter company with your dyno info and other car information to get the "correct" converter for your application.
Posted By: Chip

Re: Big Block Max RPM - 09/24/19 05:44 PM

Thanks for the feedback.

Running footbrake also....no box

I will test again this weekend.
Posted By: n20mstr

Re: Big Block Max RPM - 09/24/19 05:46 PM

just an idea, is the trans full?? and what pan is on it?


you could also put some hyd fluid in it, but that's just a bandaid
Posted By: AndyF

Re: Big Block Max RPM - 09/24/19 08:34 PM

Originally Posted by Chip
Indy 440-1 Heads Ported at Brandywine with 750 lift roller cam 1.5 ratio T&D rockers


With -1 heads and a solid roller cam you might still be making power at 7000 rpm. Usually the power is dropping by 7000 rpm with those heads and 500 cubes but it all depends on compression, cam, intake and headers. If you have a good intake (ported by someone who knows what they are doing) the power will carry a little further. Most Mopar guys run cast intakes right out of the box which kills off some of the top end power. You'll have to drive the car for awhile to see if those 4.30 gears are what you want. From what I've seen, the 4.10 gears tend to work pretty good with a 500 inch engine but it depends on where the power curve ends up.
Posted By: pittsburghracer

Re: Big Block Max RPM - 09/24/19 08:56 PM

Originally Posted by Chip
R/T .117

60 ft 1.539

330' at 4.274

1/8 at 6.658 at 103.35 MPH

1/4 at 10.723 at 109.48 MPH (but i was letting off)... My dial in was 10.75

Probably need a tighter converter...



Well let’s just say you aren’t anywhere near 766 horsepower on that pass especially at an East coast track. Heck my sons heavier (3200) pounds stock crank Edelbrock headed 360 is quicker than that and he’s no where near that horsepower
Posted By: Chip

Re: Big Block Max RPM - 09/24/19 11:31 PM

Originally Posted by AndyF
Originally Posted by Chip
Indy 440-1 Heads Ported at Brandywine with 750 lift roller cam 1.5 ratio T&D rockers


With -1 heads and a solid roller cam you might still be making power at 7000 rpm. Usually the power is dropping by 7000 rpm with those heads and 500 cubes but it all depends on compression, cam, intake and headers. If you have a good intake (ported by someone who knows what they are doing) the power will carry a little further. Most Mopar guys run cast intakes right out of the box which kills off some of the top end power. You'll have to drive the car for awhile to see if those 4.30 gears are what you want. From what I've seen, the 4.10 gears tend to work pretty good with a 500 inch engine but it depends on where the power curve ends up.


Indy intake with a 2-inch merge spacer. Dominator 4500, 1050 cfm, Carb tune by BLP...TTI headers...

410 gears may be best.

Thanks, Chip
Posted By: fast68plymouth

Re: Big Block Max RPM - 09/25/19 02:09 AM

.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.
Posted By: pittsburghracer

Re: Big Block Max RPM - 09/25/19 02:14 AM




If you can get a car to 60 foot, the rest is all downhill. Start there, because the race does.
Posted By: tubtar

Re: Big Block Max RPM - 09/25/19 02:43 AM

Originally Posted by pittsburghracer



If you can get a car to 60 foot, the rest is all downhill. Start there, because the race does.


Sort of what I was thinking.
That 60 is soft for the motor and gear , the e.t. and basically every other parameter that applies here.
Even foot braking , I'd expect a 1.4 ish number.
Posted By: Chip

Re: Big Block Max RPM - 09/25/19 09:46 AM

Lunati -Solid Roller part #53709 4800 - 8000 .738"/.738" 282/282 336/336 106/104 .022"/.024"

Tryin to make it to Mopar Madness at NED Saturday to put in sum more runs...
Posted By: racerx

Re: Big Block Max RPM - 09/25/19 11:56 AM

For a sort of comparison my e-body is 3350 race weight. 500",727,4.10,29.5 tire. My 60' usually anywhere around 1.29-1.30 with a best of 1.27 (which I think was a fluke) my mph is 139-140 with a best of 142. At 3150 race weight is this a glass/back half car?
Posted By: n20mstr

Re: Big Block Max RPM - 09/25/19 01:12 PM


IF YOUR USING A 7,000 RPM CHIP....SOMETIMES THEY ARE NOT 100% ACCURATE. MAYBE YOUR 7000 CHIP IS 6700....TRY A 7200 CHIP , ETC
Posted By: hemi-itis

Re: Big Block Max RPM - 09/25/19 02:23 PM

Long story short,,,,,,,,MSD says +/- 15% is ok.............not in my book!! I hope it's not the same when you program timing with their programmable products! runaway
Posted By: fast68plymouth

Re: Big Block Max RPM - 09/25/19 02:24 PM

Originally Posted by Chip
Lunati -Solid Roller part #53709 4800 - 8000 .738"/.738" 282/282 336/336 106/104 .022"/.024"

Tryin to make it to Mopar Madness at NED Saturday to put in sum more runs...


If you get a chance sometime, with the motor warmed up...... do a compression test on a couple cyls.
See what you get in 4 pumps, and then as many as it takes for the needle to stop climbing.

That cam has a lot of seat timing....... I’d be running 5500-6000 stall.
Posted By: dvw

Re: Big Block Max RPM - 09/25/19 03:04 PM

My car weighs 3350. Motor is 72 cubes bigger, -1 heads, 15-1. Similar intake cam timing (285/292-112). It has been quickest with a 6100 true flash, 4.30 10.5x31. Being your engine is smaller with similar intake timing and less compression I would bet it likes even more converter than mine. Best 60ft is 1.250 off the foot brake. I'd leave the 4.30 in it. Mine goes thru at 7300@150
Doug
Posted By: Chip

Re: Big Block Max RPM - 09/25/19 07:04 PM

Originally Posted by racerx
For a sort of comparison my e-body is 3350 race weight. 500",727,4.10,29.5 tire. My 60' usually anywhere around 1.29-1.30 with a best of 1.27 (which I think was a fluke) my mph is 139-140 with a best of 142. At 3150 race weight is this a glass/back half car?


3150lb with me in car and I weigh 210lb

Car is back-halfed ladder bar...glass fenders, hood and rear decklid...gutted with lexan

I will up the MSD 7AL-3 RPM Limit to an 8000 RPM module for this weekends tests...
Posted By: Chip

Re: Big Block Max RPM - 09/25/19 07:12 PM

Originally Posted by n20mstr
just an idea, is the trans full?? and what pan is on it?


you could also put some hyd fluid in it, but that's just a bandaid


2-inch deep pan

What does hyd fluid do?
Posted By: Chip

Re: Big Block Max RPM - 09/25/19 07:15 PM

Originally Posted by fast68plymouth
Originally Posted by Chip
Lunati -Solid Roller part #53709 4800 - 8000 .738"/.738" 282/282 336/336 106/104 .022"/.024"

Tryin to make it to Mopar Madness at NED Saturday to put in sum more runs...


If you get a chance sometime, with the motor warmed up...... do a compression test on a couple cyls.
See what you get in 4 pumps, and then as many as it takes for the needle to stop climbing.

That cam has a lot of seat timing....... I’d be running 5500-6000 stall.


I will test compression...

5500 stall converter from Pro-formance
Posted By: Chip

Re: Big Block Max RPM - 09/25/19 07:17 PM

Originally Posted by n20mstr

IF YOUR USING A 7,000 RPM CHIP....SOMETIMES THEY ARE NOT 100% ACCURATE. MAYBE YOUR 7000 CHIP IS 6700....TRY A 7200 CHIP , ETC


Going to an 8000 RPM Chip for testing...but I did order 7300-7500-7700-7900 chips and will work my way up.
Posted By: AndyF

Re: Big Block Max RPM - 09/25/19 09:11 PM

Originally Posted by Chip
Originally Posted by n20mstr

IF YOUR USING A 7,000 RPM CHIP....SOMETIMES THEY ARE NOT 100% ACCURATE. MAYBE YOUR 7000 CHIP IS 6700....TRY A 7200 CHIP , ETC


Going to an 8000 RPM Chip for testing...but I did order 7300-7500-7700-7900 chips and will work my way up.


How high did you turn it on the dyno? If you have the dyno sheets then you should already have the answer to your question. If peak power was 6600 RPM then not much reason to turn more than that unless you're racing in a competitive class and you're trying to wring the last bit out of the run.
Posted By: Chip

Re: Big Block Max RPM - 09/25/19 09:48 PM

Originally Posted by AndyF
Originally Posted by Chip
Originally Posted by n20mstr

IF YOUR USING A 7,000 RPM CHIP....SOMETIMES THEY ARE NOT 100% ACCURATE. MAYBE YOUR 7000 CHIP IS 6700....TRY A 7200 CHIP , ETC


Going to an 8000 RPM Chip for testing...but I did order 7300-7500-7700-7900 chips and will work my way up.


How high did you turn it on the dyno? If you have the dyno sheets then you should already have the answer to your question. If peak power was 6600 RPM then not much reason to turn more than that unless you're racing in a competitive class and you're trying to wring the last bit out of the run.


At 6800 RPM 585 torque and 757 HP
Posted By: fast68plymouth

Re: Big Block Max RPM - 09/25/19 09:59 PM

As long as it has enough spring, with the cam you have......... I’m sure the motor would feel like it’s pulling fine to 7500 or so.
Posted By: pittsburghracer

Re: Big Block Max RPM - 09/25/19 10:42 PM

It might be the dyno side coming out of most of you guys but this isn’t a top end issue. The thing is a turd in the first 60 foot to probably the 330 foot mark and until he addresses that with a better converter or chassis tuning will never run like it should. Get that sucker in the 1.35 area or hopefully better and his face will scream excitement.
Posted By: AndyF

Re: Big Block Max RPM - 09/25/19 11:17 PM

Originally Posted by fast68plymouth
As long as it has enough spring, with the cam you have......... I’m sure the motor would feel like it’s pulling fine to 7500 or so.


That is true. It might not be making a lot of power but an engine like that will just sing for as long as you hold the pedal down. I've done that with a few engines where it just sings in the lights and I think I'm going fast but then when you look at the data you see that you aren't. Once the engine leans over there isn't much point in continuing to whip it even if it sounds good.
Posted By: Cab_Burge

Re: Big Block Max RPM - 09/26/19 12:28 AM

I tell all the new racers I help to move the shift lever when it quits pulling hard.
I've seen electric tach not read correctly and be off as much as 1000 RPM when ran with a good mechanical tach in the car shruggy work
Look at the time slip and write every change down so you can look at the results later away from the track to learn as much as you can from each run and day at the track up twocents
My current S/P car picked up 2.4 MPH in the 1/4 mile by raising the shift RPM from 7000 RPM to 7300 RPM at Woodburn in July. It had ran a 8.862 at 148. MPH on the second time trial run, I raised the shift RPM from 7000 RPM to 7300 RPM and the car ran 8.864 ET at 150. MPH on the next time trail run 1 hour later. work
I have a three step on the MSD 7AL2 box, the car also has a Biondo 400 box in it to run the throttle stop and shifter, I shift it off of RPM instead of time. It will play back the last run if I hit the line lock button just before I start the run. I've seen a 200 RPM difference on the shift playback from the RPM chips in the three step also work
IHTHs thumbs
Posted By: 383man

Re: Big Block Max RPM - 10/03/19 04:35 AM

This is a slip from my 63 Sport Fury with my pump gas 493. Its a solid flat tappet cam of 264 & 270 @ .050 with .585 & .592 lift on a 110 LSA and has Indy EZ heads. I use a Luppo Dynamic 9.5 converter and I shift around 6200 when I actually do look at the tach and trap about 6400. Thats using 4.30's and Hoosier 30 x 9 radial slicks. The cars weighs right around 3700 without me. Never dyno'd but going by weight , et and mph it should be around 600 flywheel hp. You got a lot more in it and you need to find out where its lost. Good luck with it. Ron

[Linked Image]
Posted By: rebel

Re: Big Block Max RPM - 10/03/19 06:18 AM

I have a 750 lift roller & -1 heads too but I have less cubes 455, but rev to 8k each gear. I'm 2450lbs & my junk runs 8.9s @153 mph with 4.88 rear gears & a 6200 stall converter.
Posted By: moparacer

Re: Big Block Max RPM - 10/03/19 12:06 PM

Factory B block 499 here. Shift at 6800 and cross at 7100 with Indy -1's.
Posted By: gregsdart

Re: Big Block Max RPM - 10/03/19 01:42 PM

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.
Posted By: SoCalRacer

Re: Big Block Max RPM - 10/03/19 07:16 PM

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.
Posted By: Chip

Re: Big Block Max RPM - 10/03/19 11:52 PM

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!
Posted By: pittsburghracer

Re: Big Block Max RPM - 10/03/19 11:58 PM

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.
Posted By: Cab_Burge

Re: Big Block Max RPM - 10/04/19 02:45 AM

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?
Posted By: Cab_Burge

Re: Big Block Max RPM - 10/04/19 02:47 AM




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
Posted By: 383man

Re: Big Block Max RPM - 10/04/19 04:59 AM

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
Posted By: rb446

Re: Big Block Max RPM - 10/04/19 08:37 AM

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.
Posted By: JERICOGTX

Re: Big Block Max RPM - 10/04/19 10:43 AM

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.
Posted By: gregsdart

Re: Big Block Max RPM - 10/04/19 10:53 AM

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?
Posted By: fast68plymouth

Re: Big Block Max RPM - 10/04/19 05:52 PM

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.
Posted By: Cab_Burge

Re: Big Block Max RPM - 10/04/19 05:57 PM

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
Posted By: Dart451

Re: Big Block Max RPM - 10/05/19 12:49 PM

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
Posted By: BANDIT

Re: Big Block Max RPM - 10/05/19 02:14 PM

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.
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