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Anybody break a 904?
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tached_out View Drop Down
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Points: 328 		Post Options Post Options   Thanks (0) Thanks(0)   Quote tached_out Quote  Post ReplyReply Direct Link To This Post Posted: Jan/15/2020 at 3:16pm
I ran a 998 behind a 360 in my Gremlin bracket racer for years. The only aftermaket part in it was a TransGo stage 2 shift kit. I ran low 11s @ 120 mph. 60' times were 1.5 seconds. I had a 4,000 rpm 10'' converter. I staged the car in drive and sat there idling. I just whacked the gas pedal and went. I let the trans auto shift.

After about 250 passes it got a fresh set of high gear clutches, but I think it could have gone a little longer.

Even though an AMC 998 is good, if you want to go scrounging for the best internals, look for one out of a `75 and newer Chrysler product like a Charger, Fury or Cordoba with a 360 2bbl. The 4bbl cars had 727s.

The Chrysler 998 had much stronger steel caged 4 pinion planetary gear sets. The aluminum cages were so thick the gears had to be narrow. Be sure to check the factory welding on the steel cage. They didn't do a great job in the factory. 

You can also take the wavy snap ring that holds the clutch pack in and throw it away while you're at it. Use a flat snap ring and you'll have room for an extra clutch and steel. That's a free 25% increase in clutch area, the only area they're really lacking.

I'm sure I forgot to mention a few little things but that's the way I did it.

Glenn




Edited by tached_out - Jan/15/2020 at 3:47pm
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Points: 1719 		Post Options Post Options   Thanks (0) Thanks(0)   Quote BassBoat Quote  Post ReplyReply Direct Link To This Post Posted: Jan/15/2020 at 4:40pm
Thanks for the info, everyone.  Lakeside Rambler I am probably going to try it.  I already have the good 998 planetary for the lower gear ratios and had good luck with the last 998.  I am going to pay more attention at the swap meets this year and try and find a 998 case but I'm not hearing anything to scare me off of the 904.
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Points: 3553 		Post Options Post Options   Thanks (0) Thanks(0)   Quote Heavy 488 Quote  Post ReplyReply Direct Link To This Post Posted: Jan/15/2020 at 4:43pm
Easy enough to spot. Just look for the rib on top of the rear servo.
Should be just fine as the Dodge vans used the 998 behind their 5.9.
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Points: 16611 		Post Options Post Options   Thanks (0) Thanks(0)   Quote purple72Gremlin Quote  Post ReplyReply Direct Link To This Post Posted: Jan/15/2020 at 6:48pm
And Chrysler used 904s on their 360s. And the Chrysler 360s ran very well.  For drag racing I wouldnt be scared to run a built 904.
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Points: 2692 		Post Options Post Options   Thanks (0) Thanks(0)   Quote LakesideRamblin Quote  Post ReplyReply Direct Link To This Post Posted: Jan/15/2020 at 8:22pm
Originally posted by brownspirit brownspirit wrote:

Originally posted by LakesideRamblin LakesideRamblin wrote:

Originally posted by brownspirit brownspirit wrote:

Originally posted by purple72Gremlin purple72Gremlin wrote:

Originally posted by brownspirit brownspirit wrote:

Shouldn’t be too hard to find one of the beefier cases, I believe all V8 cars had them as well as 4wds.  Might be worth the wait if your rebuilding the trans anyway?  
904 was factory installed in 6 cyl cars only. 998 was on 304s...
904 can be beefed up.. 

How do you beef up the transmission case as the factory did?  Andy

Beef up the 904 internals, not the case.  In essence, it will be the same toughness of a 998 but without the same case.

It was a rhetorical question, the OP was asking a question about the strength of the transmission cases themselves, not the internals.  He specifically said that he was using aftermarket internals.  I gave him some options on where to possibly find the more desirable case. (V8 cars and 4wd, including 6 cyl) Weather the factory designation was 904, 998, or 999 is absolutely irrelevant to the topic.  Andy

My bad Andy.  
LakesideRamblin
69 Rambler 360
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"If you could kick the person in the pants responsible for most of your trouble, you wouldn't sit for a month." T. Roosevelt
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Points: 1020 		Post Options Post Options   Thanks (0) Thanks(0)   Quote brownspirit Quote  Post ReplyReply Direct Link To This Post Posted: Jan/16/2020 at 6:52am
No issue, I’m still curious as to why I was quoted in the first place, but I suppose it’s not important.  Andy
69' BBB AMX 390/4-speed

69' s/crambler project

69’ International F210d Cummins/5+4
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Points: 2692 		Post Options Post Options   Thanks (0) Thanks(0)   Quote LakesideRamblin Quote  Post ReplyReply Direct Link To This Post Posted: Jan/16/2020 at 9:47am
Andy, again, meant no offense.  He mentioned that he had a 904 case and just thought he could use his better internals with the 904 case.  I didn't catch the rhetorical nature of your question.  Maybe I'm a little slow on the uptake.


LakesideRamblin
69 Rambler 360
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"If you could kick the person in the pants responsible for most of your trouble, you wouldn't sit for a month." T. Roosevelt
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Points: 5476 		Post Options Post Options   Thanks (1) Thanks(1)   Quote SC397 Quote  Post ReplyReply Direct Link To This Post Posted: Jan/16/2020 at 1:46pm
My buddy Brad runs a built 998 behind his 426 stoker that puts out about 650hp and he hasn't broke it yet.  The car runs low 10's and maybe high 9's - after he has a cage put in. 
Brad's car in on the right.
IMG_0606 by Rick Jones, on Flickr
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Points: 1719 		Post Options Post Options   Thanks (0) Thanks(0)   Quote BassBoat Quote  Post ReplyReply Direct Link To This Post Posted: Jan/16/2020 at 2:48pm
Glad to hear that, as the 998 I built is now behind a 401. 
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