904 or 727 ?

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fishy68 said:
Ok. That explains the dramatic difference. in e.t.

A 727 capable of holding 1000 hp would cost a bunch more to build. Even if not building for 1000 hp cost always goes along with what parts you use.

If you re-read my posts (and numerous other posts I've made concerning 904's in different threads) you'll see I don't say not to run a 904. Each has their own application.
Click to expand...

I have noticed that you are giving out trans advice that is totally beyond my knowledge base, so I figured that you were or are a professional trans guy. So i can appreciate that. I have long been a proponent of the 904, every one I have had has been like an anvil and had produced great results in my bracket cars.
 
I wouldn't run either without a bolt in sprag! I have blown up 2 904s & both times the sprags pooped the bed! Cracked the case in 1 pretty good. Both were behind a 318 making maybe 350HP in a street driven 67 Fastback. I switched to a 727 because I was given a car that had 1 in it & I was sick of pulling the 904s out. I have to admit I felt like it lost some power after the swap. The 904s were bone stock except for a B&M shift kit in 1 & a Transgo in the other.
I'm probably going to put a 727 behind the stroker small block I'm building in my Dart, but thats mainly because I have a built 727 w/ a 3500 converter & a matching driveshaft sitting in my workshop just waiting for something to do. If I didn't, I'd probably build a 904, but I'd beef it up a lot more than I would if I had to do a 727 again.
People will always tend to give advice in favor of what they are using. The fact of the matter is you can make improvements in both to make it work. The 727s internals can be lightened & the 904 can be beefed up. Which way do you want to spend your money? Just don't do it 1/2 assed when it comes to transmissions. Too much can go wrong quick.
 
904 come with "bolt in sprags"...they are riveted...
 
the bolt in one is the same as the stock riveted one...just allows to be changed out faster since you do not have to drll out the rivets that one time...there is no performance upgrade on a 904, has the same number of rollers and springs...
 
I can only speak from personal experience, my 1st 904 was so destroyed inside I couldn't identify what was the root cause of it's demise.:)burnout: too many burnouts??)The sprag (among everything else) was chewed to bits. The 2nd one was an obvious failure where the ring spun in the case & cracked it pretty good. There weren't many(if any) performance parts available for the 904 back then so the 727 was my only real option. Now with the increased popularity of the 904s & my own experiences I would opt for a new sprag if I was building one now. That's just me.
 
Some really good info here. My TT car I bought a 727 from Tranzact done with koleens, billet front drum, bolt in roller sprag, etc RMVB and pro T Brake. I could not have built it for less than I paid for it. I did a parts take off before I bought it. $2200.00 delivered to my door.

I have an A999 on the shop floor and soon I will be tearing into it and building it as Tony, Cracked and the rest are doing them with a RMVB and pro brake. This will be behind a 410 stroker with 2 hits of NOS so I will be pushing the envelope a bit with it. I think the A999 already has the low gear set and an extra clutch disk in the front drum. The idea on this build is to hit it with a 100-150 shot out of the hole on the T Brake then have a 250 Fogger take over at the 1-2 shift through out the run.
 
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