• When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.

Hemi 4 speed

day1glo

Well-Known Member
Local time
1:51 AM
Joined
Mar 20, 2010
Messages
145
Reaction score
19
Location
minneapolis
Just how much horsepower and torque can an 18 spline 833 handle. Does anybody on here use the Passon overdrive 4 speed?
 
...well since nobody responded, I searched this site to see if this is an overly discussed subject. From what i could find in other threads, it Looks like a factory 4 speed is good for the street and preferably under 525hp. People who try to race with them in a heavier B body have had to repair them frequently. The best hope is if Passon ever gets ther 5speed tested and available to the public, and their going to set you back about 5Gs??
 
Thanks. I was wondering the same thing. Have you heard anything further?
 
Brewer Performance built mine. My motor goal was 650hp and they said it would easily handle that. And so far it has.
I have a McLeod perf clutch kit with the organic/ceramic disc and a SFI flywheel. Car weighs 3550 with me in it.
 
Last edited:
I agree that the hemi transmission will handle well over 650 hp. When they don't it's usually because the driver buggered the shift and messed up the syncros. If you are going racing with a lot more horsepower you can always pop for a Lenco or use Liberty upgrades.
 
It all depends on the weight of the car. A 3200 lb. car is going to be MUCH easier on parts than a 3800 lb. car. Anything over 550ish ft/lbs of torque would be a good starting point for a "slipper" clutch. They are commonly made of sintered iron or kevlar. I am currently fighting this battle in my red Charger.
 
It all depends on the weight of the car. A 3200 lb. car is going to be MUCH easier on parts than a 3800 lb. car. Anything over 550ish ft/lbs of torque would be a good starting point for a "slipper" clutch. They are commonly made of sintered iron or kevlar. I am currently fighting this battle in my red Charger.

i agree

they work fine in 12 sec cars and even some 11 sec cars. start getting down into the 10's or faster (on the track) the car has to be really light. my dart is 3800# with me in it, and i have piles of broken hemi box parts out of that car. even put a custom built slipper clutch in it and still broke the trans. if you go to a UMTR event and look at all the mopars they usually have Jerico's or G-forces. Go talk to em and they'll all tell you the same thing. don't waste your time or money on a hemi box for a drag race application. i never broke one on the street, but the dart spins on the street.

on a good note i got really good at building 833's, probably do them in my sleep lol

did this with the slipper clutch in, these gears were even cryogenic treated.
proshifted4speed004-2.jpg

proshifted4speed003-2.jpg


a few other shots of broken parts, got many more i never photographed
4speed004.gif

4speed003.gif
 
Just an observation, but that last picture shows what looks to be a 307 bearing (number on race), and that is for a 23 spline trans. The large 18 spline uses a 308 bearing, and is considerably larger. In your defense, you never stated you had an 18 spline tranny.

Mopar 833 transmissions have been used and abused for decades at the races, and have been touted as one tough SOB. Hell, Sox & Martin only used 833's in their RR. The tranny is capable of handling most anything for the street, and work well.

At the track, with all the electronic junk, injection, ignitions, etc, you add near instantaneous 0 to "Balls to the Wall" with sticky tires, and something is bound to give. I would gamble to say that all of the serious racers out there use expensive aftermarket race trannys, and for good reason.
 
Last edited:
Just an observation, but that last picture shows what looks to be a 307 bearing (number on race), and that is for a 23 spline trans. The large 18 spline uses a 308 bearing, and is considerably larger. In your defense, you necer stated you had an 18 spline tranny.

Good catch, its a HEMI box but its in a Dart so i use an A-body extension housing. all the A body extensions had the 307 bearing, even the ones that came in the S/S cars. i actually have an origional one.

in the bearings defense i don't think thats what gave up in that particular trans, she let go in high gear and i think the bearing was a victom of debirs flying around.

and im not trying to take anything away from the hemi box, there a great trans. Just like anything else though they do have limits. i know if the clutch goes back in the Dart it'll be with an aftermarket tranny of some sort, i've spent enough on on these old tranies i could have easily bought a brand new Jerico.
 
I really want to run a semi-normal clutch for street driving and a lenco st1200. I am still taking measurements and trying to figure out just how big the hole will be and how far back! I wish the UMTR site was easier to get into. I can never get logged in for some reason.
 
Not all 18 splines had the 308 bearing. The 66 and possibly the 67 trannys had the 307 bearings - 66 hemi cars for sure.

I wondered if the 68 SS hemi Darts / Cudas had the 307 or 308 bearing and it seems that mystery is solved. It makes perfect sense for Chrysler to use the STD A body tailshaft on those.

My comment on the power handling of the 18 spline is directly in line with GTS. For a street car they (and the top loader Ford) are unbeatable, but anyone who seriously races is running a Jerrico.
 
Not all 18 splines had the 308 bearing. The 66 and possibly the 67 trannys had the 307 bearings - 66 hemi cars for sure.

I wondered if the 68 SS hemi Darts / Cudas had the 307 or 308 bearing and it seems that mystery is solved. It makes perfect sense for Chrysler to use the STD A body tailshaft on those.

My comment on the power handling of the 18 spline is directly in line with GTS. For a street car they (and the top loader Ford) are unbeatable, but anyone who seriously races is running a Jerrico.
Anyone that seriously races one of these cars is running a 727, TH400 or a glide.
 
Anyone that seriously races one of these cars is running a 727, TH400 or a glide.

Yeah, but never really raced a transbrake true manual shift automatic car. I used to fall asleep driving my Trans Am with a TH400...click. click. yawn... click

I am probably going to be between 500-600Hp. thinking 4.10-4.30 gears. Maybe 11s in around 3300-3500lbs. 30x11.6 drag radials
 
Anyone that seriously races one of these cars is running a 727, TH400 or a glide.

Well, sure, but we are talking three pedals in this forum.

- - - Updated - - -

Yeah, but never really raced a transbrake true manual shift automatic car. I used to fall asleep driving my Trans Am with a TH400...click. click. yawn... click

I am probably going to be between 500-600Hp. thinking 4.10-4.30 gears. Maybe 11s in around 3300-3500lbs. 30x11.6 drag radials

With a 4 spd you will likely need more gear like 4.56, unless this is for street only. Auto's have torque multiplication from the converter, which is sort of like a secret 1st gear, but the 4 spd guys have to make that up in the rear end. I know a guy running a 10 sec B body with a Jerrico and he has 5.13's.
 
Well, sure, but we are talking three pedals in this forum.

- - - Updated - - -



With a 4 spd you will likely need more gear like 4.56, unless this is for street only. Auto's have torque multiplication from the converter, which is sort of like a secret 1st gear, but the 4 spd guys have to make that up in the rear end. I know a guy running a 10 sec B body with a Jerrico and he has 5.13's.

i had that problem with my car. 4:56 gear with a 29in tire still wasn't enough with the 2:65 first. that last box i had in it had a custom gear set that made first a 2.93, that really did wonders for it. think if i do a Jerico i'll either to another 2.93 or maybe even a 3.08 first.

- - - Updated - - -

I really want to run a semi-normal clutch for street driving and a lenco st1200. I am still taking measurements and trying to figure out just how big the hole will be and how far back! I wish the UMTR site was easier to get into. I can never get logged in for some reason.

call Hyatt racing and have him build you one. i was able to run this on the street, just had to tighten it up. even took it on over 100 mile round trip drive up to the downriver cruise one day.
P1270015.jpg

P1270013.jpg


- - - Updated - - -

Yeah, but never really raced a transbrake true manual shift automatic car. I used to fall asleep driving my Trans Am with a TH400...click. click. yawn... click

I am probably going to be between 500-600Hp. thinking 4.10-4.30 gears. Maybe 11s in around 3300-3500lbs. 30x11.6 drag radials

im with ya, having run a both a 727 and a 4 speed in the dart i can say the car is so much more fun with the stick. its deadly consistent with the automatic, and i don't ever have to work on it. But i still got a bug to use that clutch pedal, once i put the slipper clutch in it, it was as fast if not faster with the 4 gear. i just didn't get to make enough passes to get everything quite dialed in before it spit the trans out again. thats when i called it for now and shoved the automatic back in.
 
Auto Transport Service
Back
Top