904 how much power?

How much would you throw at a mildly building 904, billet drum, good clutches and steels. 4 pin steel planetarys.


Who's broken what, etc at what power level.

I'm tossing around getting rid of mine in favor of the glide as I feel it won't hold up to any more power. It's either that or I add an 300m input shaft and keep trucking with the 904.

My big SB made 778 on the dyno. My cars been 5.66 @ 120 in the 1/8 w/ 3.91 rear gear. My 904 works ok with LOTS of after market parts. If I had it to do over I'd put a glide in it. If your car is fairly light ( under 3000) the glide should be as quick or quicker. Mine has the following billet input and out put shafts. Aluminum front drum,after market front clutch spring pack. Trans act brake. Rollerized assembly,lightened sungear, rewelded planetaries, needle bearing out put shaft support, Deep Pan. It has a 2.45 low gear but I've tried a 2.28 after market gear set.I've broken lots of parts especially with the big SB. At 600-650 hp you might not need the billet shafts. The rollerized and lightened rotating assembly isn't worth much ET. I would always use a rollerized output shaft bushing in almost any application. Again if I had it to do over I would use a glide, that's what my new Daytona has.

I've got one behind 878 HP and 564 ft lbs of torque. The only thing I've wrecked so far is I melted the piston to the drum. That was due to keeping the stock single spring in there. I put the multi spring in (20 springs I think) since the factory spring will unwind at high RPMs. So make sure you put the multiple spring in the low reverse drum. I am foot braking.

It's 3650 with me in it, probably closer to 3700 after the dana swap. 1000ish hp.


I got a decent offer for my 904, just trying to justify changing stuff up.

Take the offer, it's just going to lay down on you.

I agree!

I snapped the output shaft clean two years ago in my 904 (haven't race in a year and a half) and replaced with another stocker that I had, but its only a matter of time in my opinion...that pass was on motor too! wasn't even spraying!

I just picked up to 1.76 glide cores for $100 yesterday....904 is coming out soon for a freshen and then bye bye, so I'm sure you know my opinion

One thing I feel I should point out for guys who may have ran 727s or 904s for most of their lives, and are just making the switch to a glide.

A glide in a high horsepower combination is a high maintenance option, that requires nearly all aftermarket parts. Now trust me, the aftermarket support is awesome, the converter quality and choices are great, but for many 727 racers, it's a bit of a shock going to a trans that is expensive, and requires attention regularly.

Most glide racers keep a "pass count", and rebuild at regular intervals.

I had a friend who was considering the swap a couple months ago. He wanted a Glide with a gear vendor, for a Drag Week car. I sat down and wrote out all the parts I recommended for his application, but the 7K price tag scared him off.

I have an aftermarket input shaft and pump gears in my 904, although I have never broken them I just uprgaded due to advice on this board. I've recently purchased the steel drum which takes more clutches, and has the big piston, for the next freshen up. I have the Griner LBA Brake, and other than burning up the front clutch pack, I haven't had any breakage...but I'm only at 3100 lbs.

7k? Where did the other $3500 come from other than trans?

Also, a glide built RIGHT doesn't require frequent maint, at least not in my experience. We broke two gear sets in all the years we ran a glide behind 2000hp. No problems with clutches at all

Yeah that seems high, unless it's like a gold plated reid case or something.


Glide should last just as long as any other transmission maintaince wise. It's all in who assembles it.


Most I've priced with 1.80 straight cut gears are around 1700-2500



Now looking into a 400 with a 1-2 leave. As I think it will fit in the tunnel of my f body.

hoping Billy will type up his shopping list on this one. I'm not considering switching, but interested to see either way. I'm presently having my 727 repaired again (front clutch return springs scattered in the latest weirdness with this particular unit). I also have a "mild" 904 sitting here for our iron head 360 mill. If I had a converter that I felt would be "ball park" I'd love to try it behind my W8 mill.

After you buy the Ultra-bell the powerglides are very cheap to run. My Friend and I just went through mine 2 weeks ago after it slowed up .07 and my Son said the 1-2 shift was weak. He went ahead and ordered the parts (clutches, band, and a couple of seals) so we would be ready. He came to my shop and we tore it down and the band was the issue but even after 4-5 years the clutches looked GREAT so we reused them. I installed the band and new seals and we put it back together. Total cost for the parts were under 70.00 and I have new clutches on stock for next rebuild. I broke one stock 1.82 gear years ago (125 passes) but never hurt a stock set of 1.76 gears. Now for my small tire car I went ahead and bought a set of aftermarket 1.69 or 1.64 gears for it that were pretty expensive (around 1200.00) so I hope they hold up.

Reid case, roller tail housing, 1.80 straight cuts, rollerized, deep alum pan, pro brake, 10 clutch drum, billet servos, ringless input, etc...............I can sell you all you want just like that for $3500

I suspect the other 3500 could be the gear vendor he mentioned.

Lets agree you can do a good trans for 3500. 1k for a quality converter, 2500 for a gear vendor, new shifter, new drive shaft. It adds up.

Most of my SST/SG buddies freshen them every 100 to 150 passes. Perhaps they kill more clutches because they come off the stop in high gear.

I ran a stock case Glide for many years, but nearly everyone starts with an aftermarket case these days, we typically run the JW stuff.