Pro`s and con`s 727 vs 904 for street strip use?need some help.

[ric thompson]

Building a street strip pro-streeted volare with a small block 340.My target h.p. is in the neighbourhood of 500 and would like to run an automatic with manual valve body and a 3500 stall but I`m not edjucated enuf in transmissions to know what the best choice is for my application.Any input or opinion is apreciated!

[pishta]

904 has a better reaction time over the heavier 727. The 727 is a stronger trans physically. Your going to be moving a 3600 lb car so I dont think a 9xx will be overly taxed if well built. A 727 would be a logical choice for a larger higher horse car (Super Bee, Roadrunner, etc.) plus they are more plentiful if you need core parts. 727 with the small block case are kinda rare unless you score a van.

[rumblefish360]

Race teams of old switched to the 904 series trans. They are said to be a tenth plus quicker in the quarter.
The draw back as allready said is parts are not carried at the local pizza hut like others. The tranny can handle alot of HP. If built right. Otherwise, the 727 is THEY bullit proof tranny.
I have seen chevy guys run this tranny behind there chevy S/B.
Look for the a-999 series unit. It came behind 360's.
If it's not a a-999 but one of the other 904 series trans like the 998 or lesser, have it rebuilt by a well known tranny guy to 999 specs and better.

[Fast One]

Hmm, hard to comment on this at times, it's like 6 of one or half a dozen of the other, if the 904 is built right it will do the job, I had one behind my hotty 360 for some years but in the end it died, the engine itself had a big mechanical cam, good flowing J heads, lots of stall etc, if you use the 904 tighten the clearances, try to locate a 4 pinion plantery gear set, steel pump, ex - police 904's usually have some good stuff in, another weak link with the 904 is the converter snout, they are prone to cracking, there are ways around that problem but talk to the converter maker about it.

This time around I'm going to use the 727 though.

[deadhorse66]

We just had this discussion with a guy with a 5th Ave., and opinions vary. I will tell you the conclusion we reached on that thread--904 for all out balls to the walls performance (has to be well prepped for something with 500hp), 727 if you want durability. He ended up deciding on an iron case 833 for some gear grinding fun.

[gotcha]

Just more info. I will always pick up 1.0-1.5 tenth, same condition, 727 vs. 999, with the 904 style trans quicker.

It is very strong when starting with or converting to the 999 drum and clutches. It is also very inexpensive to get the low gear set, (use the one from the 6 cylinder Mirada-Cordoba 904), usually on the shelf at about $40.00-$60.00 at trans shops.

No breakage on 450-500 hp 360-408 combos.

Have not done it yet, but considering the adapter to use on big block.

Stay away from lockup torque converter style trans for your buildup.

The specialty trans now used in serious comp eliminator cars is now a 904 based trans, handling lots and lots of HP.

[pishta]

they have a 727 to 904 adaptor? Man, i just sold my prepped 904 and TC to get a BB 727!! Bummer. It would have fit alot better too! Who sells those?

[Fast One]

I think JVX sells that stuff

[John Kunkel]

There's no doubt that the 904 will be quicker due to the lower mass/parasitic loss but for the average bracket racer the actual ET number isn't as critical as it is for a stock class racers who pioneered the use of the 904 internals.
The stock class racer has restrictions on what mods can be performed and tenth improvement in ET is a major gain. For the bracket racer consistancy is more important and the actual ET serves only to reinforce the ego.
I'll trade the durability and longevity of the 727 for the slight ET advantage of the 904.

[dave571]

I'll have to agree with John, here. I like reliability.

I have heard of 904's standing up very well, but I broke the 727 in my van last month so I'm a little skeptical of how strong things are, VS how strong they're billed to be.

727's were loved by guys from ALLmakes, who modified them for thier brand X race cars(read it in hot rod) Must be good if it will make a brand X guy see the light.

[dirty dan]

I would recomend the 727 over the 904.
In some cases such as John pointed out the 904 may have to be used.
I would rather have the dependability of the 727.
The 5tenths you may or may not gaine(depending on the aplication) doesn`t make up the lack of srength of the 904 (in stock) form.
Just my opinion.
Your choice

[superdart]

This even helps me quite a bit. My Dart has a 904 and I really didn't want to go through the cost and hassle of replacing it with a 727. Based on the experiences here I should have no problem keeping my 904 (after a rebuild and stall converter of course). My Dart has only a mild 360 (it will probably never see the high side of 425 HP) so it should be great for my application.

[pishta]

I found out why I didnt get the 904 to B/RB...$$$!!!

1) 518/904 Profiled Transmission Adapter Plate Kit with 6 Bolt Flex Plate
Part Number: AA760P6
Profiled Billet Aluminum adapter kit. It is shaped the same as the transmission bell housing for a sleeker look. Kit includes 6-Bolt Flex Plate. These kits allow you to take a 518 or 904 and bolt it to a big block/HEMI Engine.
Our Price: $499.95
More Details...



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2) 518/904 Profiled Transmission Adapter Plate Kit with 8 Bolt Flex Plate
Part Number: AA760P8
Profiled Billet Aluminum adapter kit. It is shaped the same as the transmission bell housing for a sleeker look. Kit includes 6-Bolt Flex Plate. These kits allow you to take a 518 or 904 and bolt it to a big block/HEMI Engine.
Our Price: $599.95
More Details...



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3) 518/904 Transmission Adapter Plate Kit with 6-Bolt Flex Plate
Part Number: AA760M6
Billet Aluminum Adapter Kit. It can also be fastened to the frame rails for a true mid plate application. Includes 6-Bolt Flex Plate. These kits allow you to take a 518 or 904 and bolt it to a big block/HEMI Engine.
Our Price: $469.95
More Details...



--------------------------------------------------------------------------------

4) 518/904 Transmission Adapter Plate Kit with 8-Bolt Flex Plate
Part Number: AA760M8
Billet Aluminum Adapter Kit. It can also be fastened to the frame rails for a true mid plate application. Includes 8-Bolt Flex Plate. These kits allow you to take a 518 or 904 and bolt it to a big block/HEMI Engine.
Our Price: $559.95

[Fast One]

YIKES !!!!!

Have to be really serious to get one of them...

[John Kunkel]

Ultrabell http://www.auto2000.com/jw/index.htm is the better way to go and costs less than $300.

[pishta]

Thats better! DQ> What is the difference between a 904 TC and a 727 TC? ring gear diameter?

[6packdart]

well lets see ive been useing the 904 for about 30 yrs broke a few . they have a little lower first gear ratio than the 727 . in the early days you couldnt even fine a converter for one lol so i used 6cyc from a truck give you about 2000 stall for 45 to 50 $ ive had manual valve bodys in them cheater bodys so its up to you my friend plus they wiegh about 100 lbs less than a 727 run a cooler youll be fine . 72 pro street dart 340 an you got it 904 . you can fine wider bands in truck trans the old 6cyc ones they have them in your local trans parts houses good luck

[George G. Leverette]

There are a few exceptions to the 727 never breaking myth, parts are readily available to repair the 727 which is an indication that they break and often. I have two and both have been rebuilt, one in the 74 Duster 3 years ago and the one in the 340 1,500 miles and now it will not engage any forward gear. The park rod fell out at about 500 miles and was reinstalled now this. Every 727 I have owned has needed some repair, what type transmission are we compairing to determine their superiority? what is the life expectancy before over haul? How many miles before rebuild? What were the driving conditions and geographic area where this magic was performed? repeating magazine article quotes is not helpful, real life experiences are factual information and shouild be passed on to be assessed.

[Fast One]

Here's a picture of some 904 damage, ran behind my big mechanical cammed 360 for some years, did a good service until it went bang, to cut a long story short I think the 904 was just getting tired & finally let go in the end.

[dave571]

I too have broken 727's, but have also had problems with 904's.

The bottom line is that NOTHING is bulletproof. Not 727's not thm400's not C6's

Not 8 3/4's not dana 60's not ford 9" not chevy 14 bolts.

Mileage, shock loading, improper rebuilding, manufacturing flaws, all cause failure.

New car service departments are busy all the time fixing broken components on brand new cars. New or old it makes no difference, everything breaks.

We've(street performance guys) got it fairly easy compared to the stuff I've seen 4X4 guys break. A friend of mine(GM guy) was unimpressed that the 427 industrial chevy in his monster truck(5"body lift,4"suspension lift, 37" super swamper tires, all on a 3/4 ton chevy chassis) failed after 8 consecutive weekends of abuse. The engine managed to break about 6 axles, two clutches, screw his transfercase so he had to hold it in 4 wheel drive, and eliminate 1st and second gear. Then he went to small blocks. Hasn't broken anymore driveline parts, but hasn't put an engine in yet that would last more than a weekend. Canada day long weekend he even changed the motor while in the bush(don't ask me how) The one he threw in only lasted him the afternoon.

That in mind, it doesn't bother me that the only thing I've broken on the van so far is my 727.