What gear ratio for a street car w/occasional track use?

What Gear Ratio for Street with 3-4 time a year track use?


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I have an almost identical set up as the OP with the exception of an automatic transmission and I'm running 3.54 gears and 28" MT drag radials. I would love to change to a 3.91 or higher rear gear, but I have to drive at least thirty minutes on the highway to get anywhere in this town and the nearest drag strip is an hour and a half away. Until I can add an OD of some sort, I'm sticking with the 3.54 gears.
 
I thought after 1970 all 4 speeds were the 2.47 low gear? My 72 Demon was a 2.47 low, interlocking lever side cover box.
I cannot argue about that cuz I have no first hand factory knowledge. I had a 2.47 box and got rid of it because the low gear was not happy on the start line until about 4.10s or better with a SBM. My understanding has always been that the close ratio box was a Trans Am box, and came in with the 70up Barracuda/Challengers.
 
With what 28" street tires? I want those!!
If I had a 408, and that's all it would do with a starter gear of 3.55x2.44= 8.66, on street tires, I'd be disappointed too.

That 2.44 only came in the Hemi-boX. If you have a 1x23 input then you have either a 2.66low, or the waaaay less common 2.47low, T/A box. There was a third box, in the first-gen Barracudas with a 3.09 low. You shouldn't be needing that one,lol.
The 2.66 box has a 9% better low gear and slightly wider ratios than the 2.47.. And the 3.09 box has a 16% better low gear than he 2.66, and the rest are the same. Here are the ratios;
2.47-1.77-1.34-1.00 and splits of .72-.76-.75 Close ratio 70 T/A
2.66-1.91-1.39-1.00 and splits of .72-.73-.72 Common
3.09-1.92-1.40-1.00 and splits of .62-.73-.71 1st-gen Barracuda deep-low

It was the 2.47 ratio that I meant not 2.44. My transmission is the interlocking cover 72 trans.

After my first initial burnout my Mickey thompsons seem to have pretty good traction. Running them at 20 psi.

I'm thinking I'll hold off doing anything drastic until I've driven the car more on the street and after the nationals when I've raced it. I've only driven this car on the street with the big tires three times.

As a matter of fact my traction test last weekend was probably not a good test because it's occurring to me that my revving to 3k to launch it was on the way to a big car show at a stoplight. I had a 12x12 foot canopy in the trunk, a cooler full of ice and food in the back seat, 2 chairs, and a propane portable bbq along with a passenger that weights close to 300 pounds. Which as a side note broke my Procar seat when I punched it and took off from a 20 mph role after I did my smaller burnout across the intersection. His seat sheared all the teeth off the reclining part and he slammed into the back seat. Needless to say those seats which were 2 weeks old got pulled out and returned. Original lowback buckets are in now.

I realize track launching will be different so I'll still have to experiment with rpm levels but I'll have to do more on the street testing now that I don't have 500 or 600 pounds of added weight in the car.
 
my car is still in build mode. how does that fly wheel feel on street ? quick revving but doesnt stall out from stoplights I hope ....
It is great on street and revs very quickly. No, it does not stall out at lights, idles very steady even with the 106 degree LSA cam. Rolling out from a stop is also a non issue.
 
Great ! I was hoping it would be the happy medium between an aluminum one that would be jumpy and a heavy 30 lb one that would blow the tires off on launch.
 
Hah, yeah;
I remember one-time,piling four mature men into my 367 Barracuda,for a quick spin around the block. My car was already fat at 3650 pounds, with just me in it. Now add nearly 1000 pounds of giddy 50-something year olds, and I knew as soon as I slipped the clutch out, there would be no showing off on that ride,lol.
 
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I’ve changed from 3.55 to 3.91 a few times and always thought that it wasn’t enough so I voted for 4.10s. For ur short trips I would go 4.30s. Kim
 
Now got 3.55s but not really happy with them. Also going to 292 purple cam so definitely need more gear. 3.91s I have ready to go in.
 
I've decided that I think I want to swap out my 3.55 gears in my 68 Dart 408 stroker. It's a 4 speed manual with the 2.44 (I believe that's what it was?) 1st gear. After this last tuning session its making roughly 500 hp and 540 ft/lbs torque. I'm running a 28x12.5-15 Bias ply wrinkle wall tire.

I'm just not as happy with the 3.55's as I thought I would be. Thinking I should have gone 3.73 or 3.91's.

It will spend 95% of its time on the street with spirited stoplight to stoplight driving and some highway to get to shows within a half hour or so. Probably 3-4 times a summer I'll take it to the track. Am I crazy wanting to change the gearing being its not a track car?

Currently it cruises at about 3000 rpm at 70.
Is it a M/T Sportsman Pro....?.
 
Lowest was a 2:66 on the wide ratio...,I don't remember enough, about 833...boxes...
I have seen the difference in 4 speed gear boxes ,in basic street mills.
We still don't have feed back ,so how ...can we help him. ....?
 
With what 28" street tires? I want those!!
If I had a 408, and that's all it would do with a starter gear of 3.55x2.44= 8.66, on street tires, I'd be disappointed too.

That 2.44 only came in the Hemi-boX. If you have a 1x23 input then you have either a 2.66low, or the waaaay less common 2.47low, T/A box. There was a third box, in the first-gen Barracudas with a 3.09 low. You shouldn't be needing that one,lol.
The 2.66 box has a 9% better low gear and slightly wider ratios than the 2.47.. And the 3.09 box has a 16% better low gear than he 2.66, and the rest are the same. Here are the ratios;
2.47-1.77-1.34-1.00 and splits of .72-.76-.75 Close ratio 70 T/A
2.66-1.91-1.39-1.00 and splits of .72-.73-.72 Common
3.09-1.92-1.40-1.00 and splits of .62-.73-.71 1st-gen Barracuda deep-low
Now I read it...
Back to questions, to the o.p.....
You're not flying Caitan Kirks "Enterprise " ,without "Spock or Scotty " ,on board...
We can help you ,be we need to what your engine has inside ,your rear gears ,transmission set up (Yes, including clutch ),...
You give you specs ,makes IT SOLO MUCH EASIER ,...avoiding frustration everywhere. ..
Please? We help you ,step by step.... this doesn't happen overnight
Nice to meet you :
Abodybomber / sans Tim.
 
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Stock flywheel, I would not trust that.
I would spend money on a quality SFI one before gears.
I've been using stock Flywheels for a long time, 20 yrs with a Lakewood scattershield and bellhousing never had any issue with a stock flywheel and have not had any clutch "explosions" yet either.
Everything is balanced the clutch goes with the flywheel to be neutral balanced with the rest of the rotating assembly
 
I've been using stock Flywheels for a long time, 20 yrs with a Lakewood scattershield and bellhousing never had any issue with a stock flywheel and have not had any clutch "explosions" yet either.
Everything is balanced the clutch goes with the flywheel to be neutral balanced with the rest of the rotating assembly

If flywheels seldom fail then why run blowproof bellhousings ?
And if stock flywheels dont fail often then SFI steel failures must really be non existant.

these are meant to be legit questions... not trying to be wise guy.
 
I got an idea; let's start a new thread titled
"in 20 years have you ever blown up a stock SBM flywheel?"
Or; "at what rpm did your stock flywheel blow up?"
Or some such thing
Let's see how many responses we get.
Seriously; I would really like to know; not being a dick.

I'll be second; in a total of 40 years of running mopar manual transmissions, mostly street (like 99.98% or something) ,with stock flywheels,in 5 different cars, and at up to 7200 regular shifting.......zero failures. I estimate that to be over 300,000 miles.
Next;
 
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If flywheels seldom fail then why run blowproof bellhousings ?
And if stock flywheels dont fail often then SFI steel failures must really be non existant.

these are meant to be legit questions... not trying to be wise guy.


It's not just the flywheel that can fail. The covers fail, the pressure ring can fail and the disc can fail. None of which is good.

The first explosion I saw with my own eyes was a Pontiac. Guy thrashed all night getting it back together and didn't torque the flywheel bolts. It wasn't good. Bought a scatter shield pronto and have never not run one, with the exception of a few months here recently.
 
I would have thought that stock flywheels fracturing would be the main culprit but I have never witnessed it happen.
 
I would have thought that stock flywheels fracturing would be the main culprit but I have never witnessed it happen.
Cranks break, blocks split, balance jobs have been neglected, wrong flywheel... all those things happening at the track, harsh *** conditions compared to daily driver grocery getter...and added to the clutch plates that yellow rose stated and the rest.

That's why they have proof bell housings, shields and blankets. All of our cool hot rod'r catalog bolt ons , parts n pieces come from racing development.
 
If it's a good idea I'll get the flywheel too I guess. What causes a flywheel to blow typically?

I think I'll start off with a 2500 launch at the track. Then go up 500 rpm at a time.


High RPM's.

Don't count on getting a lot of passes at the NATS if you are doing fun runs. You may be better off to go to a local track before then to experiment with your launch RPM. Or find a deserted area somewhere to practice.

I've actually beaten some 440 powered cars with my street 318 because they were spinning and I was leaving just over idle.
 
High RPM's.

Don't count on getting a lot of passes at the NATS if you are doing fun runs. You may be better off to go to a local track before then to experiment with your launch RPM. Or find a deserted area somewhere to practice.

I've actually beaten some 440 powered cars with my street 318 because they were spinning and I was leaving just over idle.

I probably won't have a chance to make it to the track before the Nat's so I guess I'll just have to be happy with 1 run or maybe 2. Unless I do a late entry for the stick class :D
 
I’ve seen a few clutch failures. A guy lost his foot when 1 exploded. Another 1 part of the disc went through the roof and part went down into the paved parking lot. These were on Chevy small blocks. Kim
 
Does anyone actually check for current SFI cert ?
if so ..how do you go about recertifing a bellhousing ?
 
Does anyone actually check for current SFI cert ?
if so ..how do you go about recertifing a bellhousing ?


Sometimes. It mostly depends on who you are. Since I'm a prick bastard, they always wanted to see my certification. Most other guys they just looked to see if they had a can and not a stock bell housing.

IDK what just the recent costs, but if you get a window installed at the same time, it costs $335.00 for the window and the cert.

If you have a Lakewood or Browell can just call Holley, as that's who owns them and they will cut you a repair order and you send the can to Iowa. When it comes back it will look freaking brand new.
 
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