a note on 904s and 727s

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djwhog

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Hey I st want to apologize to abodyjoe. I did not mean to get out of line. But I have really done more than 1000 trannies in more than 35 years. I have seen them all blow even done by others that are suppose to be the best. I just felt very put down espec. when a guy tells me what a ford tranny guy said. Anyway someday I can tell you all about the similarities in a c-4 904 and c-6 727. Had a few family members that have the real deal on how those trannies came about for Mopar and Fomoc.

Anyway, yes they can all be made to hold together. But the weakest links are the input, output shafts and the sprags. That was why the 904 was also know as a TF-6 for the /6 and low end LA motors and a 727 is known as a TF-8 for V8s HD use police taxi etc. and high output engines. But as Joe and others said you can beef it up for more punishment to a point for enough $$$, I did mention some of the parts one needs to change in that post we all went down the road on. And again I am sorry it got heated!

Also I had a freind in High School loose his right foot when his 904 exploded. I should have spoke about this I know. And have seen a lot of 727s blow too, but fewer. MOst times it is always the sprag that goes.

I am just concerned when someone says that they make a real 450+ HP and stick it in fornt of a transmission. Even a stick shift should have a scatter sheild too. Had another college buddy end up in the hospital when his 65 Malibu with a 327 and an M22 exploded his 10.5 steel flywheel at 7k rpm going into 2nd.

So a word of caution and make sure you at least do a bolt in sprag, go easy on water burnouts and get a sheild or at least a blanket.

Here is a link to the same topic. Something really worth your well being to keep in mind guys with these high output engines everyone is doing these days...

http://www.moparchat.com/forums/showthread.php?t=104515
 
I've never seen one explode but have taken care of a patient whose did. There is no substitute for safety in a hobby like ours. Good parts all the way. I put a scattershield on my ride for the increased protection and a drive shaft loop as well. I can only go by what Keisler says the TKO 500 will take. My car will mostly be street driven but I like the added safety which some would say is overkill. 904's and 727's can be built to be bulletproof. Everything has a weak point. If you can stregthen it...why not? Losing a limb is pretty devastating....try comforting a young person before you put them off to sleep for the surgery that will remove the rest of their mangled limb. Sucks....

Thanks for the note Dave
 
Okay man, in laymans terms, please help me to understand all this. Why do your feet get hurt when a tranny "explodes"? What comes up? What does a blanket mean? And how does a splatter shield work/fit? Can you put one on an automatic? Should you?

I have my nice little all stock original cable shifted 904 behind a 318, but hope to put it behind a 340 soon. I knew I would have to have it "beefed up" but what else should I be doing?
 
Picture the parts inside the case like the front drum. It is metal and is gear reduction driven and you have clutches, bands that spin to allow more leverage out of your engine. Like in low you are at 2.45 to 1 of your engine. You you have this incredle load and when a drum explodes it is a metal grenade with razor sharp metal spinning 1000s or RPMS. it is a mega powerfull skill saw in the wild. It will and can cut the trans case in 1/2, take that aluminum with it, then cut up through the floor and take that sheet metal too right at about your feet and the dash.

Driving with caution is the best exercise of common sense. But most of us that build high HP cars get on them a lot from time to time. So I would just say as one of the members on the site has for a signature.

No Kill Like Overkill!

Means make sure you put safety into the car too. You are making more than a factory engine was designed for, more than the brakes, suspension, trans, rear end, frame etc.

Remmeber, they built these ars to make a profit. So a lot of corners were cut to get by. Not as many as today, but still a lot. That is whey the higher HP options encluded bigger radiator, trannies, rear ends, brakes etc.. However, does not mean you can't beef up what you got, but think about it??
 
65s said:
Okay man, in laymans terms, please help me to understand all this. Why do your feet get hurt when a tranny "explodes"? What comes up? What does a blanket mean? And how does a splatter shield work/fit? Can you put one on an automatic? Should you?

I have my nice little all stock original cable shifted 904 behind a 318, but hope to put it behind a 340 soon. I knew I would have to have it "beefed up" but what else should I be doing?
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The scattershield (thick steel) helps to keep the exploding parts from coming through the floorboard and the blanket keeps alot of the exploding parts from spraying out from under the car and onto the track. As far as I know.
 
I have a 904 that is behind a late 318 police engine, the 904 was with it, it has the wide ratio gears and steel planetaries, and aside from better heads and intake/carb it is the way the police ran it. Now, I intend to lightly cam it, 219/489 hughes cam, and put on an air gap and cd ignition, and after that I had planned on a 50 or 75 shot of nitrous. Now, again, my build up is mild, but like doug above, I like my feet, do I need to put in a shield and/or blanket? I won't even be going to a much higher stall, if at all, with this cam, so is this something I will need? I do not intend to race, except maybe a run or two for fun someday, I just like wicked little street ripper barracudas. If this is a real concern for a situation like mine, I would like to know now, before I get ahead of myself, plus, my wife will be driving it,too, and believe me, her RT is better than mine, and she can put the hammer down so I want her to be as safe as can be. How much power should I consider the limit for my current setup? I estimate it will hit 325 hp or so after it is all done, and 375 on the bottle, 400 tops. She probably won't hit the button that much, and neither will I, just on special occasions, ya know! Do I need a scattershield and blanket?
 
stroker mike said:
I have a 904 that is behind a late 318 police engine, the 904 was with it, it has the wide ratio gears and steel planetaries, and aside from better heads and intake/carb it is the way the police ran it. Now, I intend to lightly cam it, 219/489 hughes cam, and put on an air gap and cd ignition, and after that I had planned on a 50 or 75 shot of nitrous. Now, again, my build up is mild, but like doug above, I like my feet, do I need to put in a shield and/or blanket? I won't even be going to a much higher stall, if at all, with this cam, so is this something I will need? I do not intend to race, except maybe a run or two for fun someday, I just like wicked little street ripper barracudas. If this is a real concern for a situation like mine, I would like to know now, before I get ahead of myself, plus, my wife will be driving it,too, and believe me, her RT is better than mine, and she can put the hammer down so I want her to be as safe as can be. How much power should I consider the limit for my current setup? I estimate it will hit 325 hp or so after it is all done, and 375 on the bottle, 400 tops. She probably won't hit the button that much, and neither will I, just on special occasions, ya know! Do I need a scattershield and blanket?
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Never a bad idea for a least a blanket as a safety measure. Better safe than sorry. All it takes is one wicked burnout or broken u-joint. if that happens you should at a minimum always inspect the sprag. But it is cheap insurance on a performance car.

Mine has one just like I used to run a scatter sheild. It is just good protection. Most tracks require shaft loops, blakets and or sheilds, and then 1sec and faster need roll cages etc. These are required for a reason. I think those that made the rues know and have seen what they are talking about.
 
Use the NHRA rulebook as a guideline. Install all of the safety equipment for the next performance level higher than you anticipate your car will achieve. Always use SFI approved parts when you can.
 
Let me tell you my story. When I was young and dumb(er), I put all my money in a 340 engie ,tunnel ram two 660 w-2 heads nice solid cam, 4.30 gears,blah blah blah. A scatter sheild? Hell that ain't gonna make me go fast!
So one day when I had my mom, ( of all people) in my car, i thought I'd show her what a great mechani/ driver she had raised. I tached her up to 7000, side stepthe clutch pedal, and man he came alive! Hit second gear and the last hing i heard was booooooooom, flywheel came apart ,on piece came thru the floor board cut my shoe,continued thru the dash, tookout the radio, went thru the windshield,and i never did find out where that pice went, My poor om pissed herself. And I had that deer in the headlght look for a few minutes. Well it broke the back of the block,both ears of the motor broke off leaving 3 bolt to hold a transmission,so needless to say the block was junk. Not to mention what the bottom of the car looked like. Well i think yawl get the point. I live by my motto, " IF YOUR GONNA BE DUMB, YOU GOTTA BE TOUGH"
 
Let me tell you my story. When I was young and dumb(er), I put all my money in a 340 engine ,tunnel ram two 660 w-2 heads, nice solid cam, 4.30 gears,blah blah blah. A scatter sheild? Hell that ain't gonna make me go fast!
So one day when I had my mom, (of all people) in my car, I thought I'd show her what a great mechanic/ driver she had raised. I tached her up to 7000, side step the clutch pedal, and man she came alive! Hit second gear and the last hing i heard was booooooooom, flywheel came apart ,on piece came thru the floor board cut my shoe,continued thru the dash, took out the radio, went thru the windshield,and I never did find out where that piece went, My poor mom pissed herself. And I had that deer in the headlght look for a few minutes. Well it broke the back of the block,both ears of the motor broke off leaving 3 bolt to hold a transmission,so needless to say the block was junk. Not to mention what the bottom of the car looked like. Well i think yawl get the point. I live by my motto, " IF YOUR GONNA BE DUMB, YOU GOTTA BE TOUGH"
 
Hey I st want to apologize to abodyjoe. I did not mean to get out of line.
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no need bro... we can have a heated debate and have no hard feelings.... we are all a family and can fight like cats and dogs and the next day its like nothing happened.... know what i mean?
 
So what kind of shield do you put with a an auto 904? What about kevlar under your carpet?
 
I would think that you would want the kevlar to be backed by the sheetmetal, not carpeting.
 
i had pix of a 727 explosion in a cuda.. cant seem to find them...???
 
If you look at the 2nd sticky post on the top of the trans section there's a pix of a blown 727 that Chris posted. Their real ugly when they go.
 
I'm crazy I guess, I built a 450HP 440, 727, and Ford 8.8 3.73 Rear. She's going to be just a cruiser, and maybe one or two runs down the strip. Not trying for 10 Second car. Should I put a shield in?

Thanks
 
the sprag can get a hairline fracture when going from a water burnout (tires spinning very fast) and then coming out of the water to dry pavement. anytime after that the transmission is set and likely to grenade when stepped on! this is most likely with Hi-powered engines and sticky racing compound tires, but it can happen even in a street stocker.
when i was young, riding with a boyfriend in his SHARP, black, 57 belair with red bucket interior, built 283 vette motor, 4:88 gears and 4 speed trans we came across this guy with a 68 chevelle 402 bigblock...they had been "bench racing" for a few weeks i guess and couldn`t resist putting an end to it.
this was back in the day and we were usually at street races every weekend and sometimes even on weeknites. it was real common.
anyways we were fender to fender at about 100MPH in 4th gear and had the Chevelle by a car at 110 MPH...that 283 was getting pretty wound up with those 4:88`s and at around 6500RPM the clutch/flywheel came apart! there was a huge explosive noise, the car filled with smoke, we almost crashed with the other car and when we finally stopped and realized what we lived thru we felt very lucky!!! (we did win the race after all...haha) ...there was a path of parts laying on the road behind us of the broken bits, transmission, driveshaft shards, etc...it would`ve been funny, almost cartoon like if it wsn`t so scarey! there were holes in the floor all around our feet and the clutch disc was stuck in the dashboard, cut right thru sticking out the top of the dash! it would`ve taken a leg right off! the engine was dragging the road supported by the headers and friends were picking up parts out of the road. another friend scrambled to get his tow truck and just about then the cops showed up...lucky no one got hurt or arrested for drag racing!
obviously the car had no safety equipment, no, harnesses, roll cage, scatter shield or driveshaft loops...we were just damn lucky and i knew alotta people who died street racing back in the day! one guy took out a telephone pole about 15 feet in the air at 100MPH...woulda been a good trick if he had lived thru it! we had raced (and beat his Pontiac) earlier on that fateful nite...
 
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