wich is faster? more dependant? cheaper? I noticed everyone recomends steel drum for 727 but seen nothing about 904. I will be running this behind 3000Lbs dakota with about 550hp, no trans break. what modifications do i need?

I have no experience W/ a 904 but I think the 727 is a stronger trans yet it is heavier and takes more hp to run vs a the 904.

904 is going to be faster!! 550 hp no problem

I`ve ran a 904 behind my 550hp small block for years with no problems.

Depends what you're looking for & how much HP you're making. IMO a 727 is the only thing for a big-block, but awith a small-block, moderate HP, why carry the extra weight & draw the HP to drive it? You need to be a little more specific what you're looking to do.

if you're like most of us racers we start out running 12 11 10 9 etc do it once and don't look back.727

what modifications are needed to 904 to handle 550hp small block drag race only

I have a 904 with a brake, its a fast and fairly reliable.It has a fair amount of race parts inside.The 727 is about .10-.15 slower behind a SB but more reliable than a mostly stock 904. If I had it to do again I would look serously at a glide though.

I always wanted to know what's faster in a low 9 second car the 904 or 727? give me your opinion

ok let get back to the real world I'm not talking $5000 plus trans. they're using a 904 where every hundred thousands count.so how much faster is the 904 vs 727 in a ss/aa hemi car?

In the mid-'70's, Chrysler did some extensive testing between the 727 and 904 transmissions. I believe they were in Stock and/or SS vehicles. If both transmissions are equally prepared and have torque converters that perform the same, the 904 was found to be .10 - .15 faster.

Engine and vehicle weight differences can affect the specific numbers. A heavier, lower HP vehicle would probably see a little more benefit as compared to a lighter, higher HP vehicle.

I had a w2 360 with 727 and 8" turbo action converter. Switched to 904 with 8" turbo action converter. Picked up almost a 1/10th in the 1/8 and close to 15/100's in the 1/4. All we did was good clutches and band with the turbo action transbrake valve body. 600-700 passes between rebuild jobs. It never failed on us we just freshened it up every 18-24 months.

back somewhere around 1992..i switch from a 727 to 904, both using a turbo action 3800 series converter that flashes to around 4800 rpm...and the 904 was .15 faster and almost 2 mph...

never raced using a 727 again...

A 904 behind a 550HP 3000lb car will last a long time.

It doesn't need a billet drum like a 727 because the smaller diameter has much less inertia, meaning it won't blow up like a 727 will.

Depending on how much RPM you're gonna run, you might want to upgrade the high gear drum release spring, but I've run them up to 7200 on a 340 duster without issue.

Basially just needs a manual valve body, 5.0 lever, good bands, clutches and steels, and a 5 clutch high gear drum (with matching machined pump). That should last a long time.

The other nice thing is that low gear sets are plentiful, and an easy swap.

You just have to be careful swapping different year hard parts around in a 904 because there are some subtle differences that can cause problems...

What is the plan these days for bands in the 904 ?

There is some debate to use a rigid band or a flex band. The wide flex bands are easier to come by, most of the ridgid stuff is narrower. I don't know if anyone is making the wide ridgid band again or not...

This thread has me thinking of swapping out the stock 727 in our 1972 Dart and swapping in a 904 with some good clutches & steels, shift kit, and a new lever.
Looking to do as much racing with it as possible this year, but it's a street car.

As was already stated, what else is needed to make the 904 hold up forever?

Switching from a 727 to a 904 and picked up a .15 tenths in the 1/4 is good but spending at least $1800 for a 904 trans and converter to be isn't worth it.