Moparts

Small block 727 brackets

Posted By: 6PAX

Small block 727 brackets - 08/06/22 11:47 PM

I plan on converting my 340 Dart from a 4-speed to a 727 automatic this coming winter. I know the small block automatics came with a support bracket on each side of the bellhousing. I have TTI headers and from what I have read, apparently the brackets won't fit with headers. What I would like to know is, will not having the brackets be an issue?
Posted By: TJP

Re: Small block 727 brackets - 08/07/22 12:27 AM

No, unless you're producing ungodly amounts of torque with sticky tires, a suspension that plants them and loose converter twocents beer

Myself I'd leave the 4 spd in it. thumbs
Posted By: 440newport

Re: Small block 727 brackets - 08/07/22 12:48 AM

In my experience the driver side brace still fits with headers, but the passenger side is a no go.

I don't think they are needed personally. but I guess the factory must have thought they were needed, why else would they spend the money on them? But on the other hand, you would think a 4 speed would see higher shock loads than an auto, and yet there are no bellhousing with provisions for those braces. shruggy
Posted By: mopars4ever

Re: Small block 727 brackets - 08/07/22 01:19 AM

Had TTI headers on mine and ddin`t have the brackets on mine with no issues.
Posted By: IMGTX

Re: Small block 727 brackets - 08/07/22 02:00 AM

It has been my experience that more small blocks are missing them than have them and they never seem to have any problems.

The drivers side one especially gets tossed when the starter is replaced by the longer version which won't clear it.
Posted By: TJP

Re: Small block 727 brackets - 08/07/22 03:22 PM

Originally Posted by 440newport
In my experience the driver side brace still fits with headers, but the passenger side is a no go.

I don't think they are needed personally. but I guess the factory must have thought they were needed, why else would they spend the money on them? But on the other hand, you would think a 4 speed would see higher shock loads than an auto, and yet there are no bellhousing with provisions for those braces. shruggy


I believe I heard from a reputable source whistling the reason was, one the higher level driveline executives had a relative with a metal stamping company that wasn't doing to well. The relatives wife was involved in uhh ARRANGING the contract, LOL shock shruggy beer
Posted By: 500ciDuster

Re: Small block 727 brackets - 08/07/22 04:35 PM

TJP, that makes sense!
Posted By: FurryStump

Re: Small block 727 brackets - 08/07/22 04:48 PM

Unless you have the 727, I would go 904, it would need a different driveshaft than the 727, but I would not put a 727 behind a small block. I just changed from a 727 to a 904 and all said and done will have picked up 2.5 to 3 tenths. Now, I increased my flash rpm by 300, in the same dia converter. Both were PTC 9.5” converters. I also changed to the low gear set inside the 904. I also went aluminum for the driveshaft. So it is not just your typical 727 to 904 swap, but no more 727’s for me. Just not necessary. As an added benefit a much lower risk of shattering the drum.
Posted By: John_Kunkel

Re: Small block 727 brackets - 08/07/22 06:12 PM

Because the SB isn't a skirted block like the BB, more of the bellhousing extends below the block with no support; that's why the factory added the struts.
Posted By: Sniper

Re: Small block 727 brackets - 08/07/22 06:26 PM

Originally Posted by FurryStump
Unless you have the 727, I would go 904, it would need a different driveshaft than the 727, but I would not put a 727 behind a small block. I just changed from a 727 to a 904 and all said and done will have picked up 2.5 to 3 tenths. Now, I increased my flash rpm by 300, in the same dia converter. Both were PTC 9.5” converters. I also changed to the low gear set inside the 904. I also went aluminum for the driveshaft. So it is not just your typical 727 to 904 swap, but no more 727’s for me. Just not necessary. As an added benefit a much lower risk of shattering the drum.


This isn't the race forum and no asked about picking up a tenth.
Posted By: TJP

Re: Small block 727 brackets - 08/08/22 02:31 AM

Originally Posted by John_Kunkel
Because the SB isn't a skirted block like the BB, more of the bellhousing extends below the block with no support; that's why the factory added the struts.


I still like my line of ? beer
Posted By: FurryStump

Re: Small block 727 brackets - 08/08/22 02:09 PM

Originally Posted by Sniper
Originally Posted by FurryStump
Unless you have the 727, I would go 904, it would need a different driveshaft than the 727, but I would not put a 727 behind a small block. I just changed from a 727 to a 904 and all said and done will have picked up 2.5 to 3 tenths. Now, I increased my flash rpm by 300, in the same dia converter. Both were PTC 9.5” converters. I also changed to the low gear set inside the 904. I also went aluminum for the driveshaft. So it is not just your typical 727 to 904 swap, but no more 727’s for me. Just not necessary. As an added benefit a much lower risk of shattering the drum.


This isn't the race forum and no asked about picking up a tenth.


True, but he’s running headers so he probably isn’t a restoration/date code/part number guy. If he has nothing on hand there is no reason to run a 727, except if he cares that it might have come with one originally. Racing or not, do you want to run a less efficient transmission? More power to the wheels, better mileage, safer, comparable cost. Valuable info no matter what you are doing with the car.
Posted By: forphorty

Re: Small block 727 brackets - 08/08/22 11:31 PM

Originally Posted by FurryStump
Originally Posted by Sniper
Originally Posted by FurryStump
Unless you have the 727, I would go 904, it would need a different driveshaft than the 727, but I would not put a 727 behind a small block. I just changed from a 727 to a 904 and all said and done will have picked up 2.5 to 3 tenths. Now, I increased my flash rpm by 300, in the same dia converter. Both were PTC 9.5” converters. I also changed to the low gear set inside the 904. I also went aluminum for the driveshaft. So it is not just your typical 727 to 904 swap, but no more 727’s for me. Just not necessary. As an added benefit a much lower risk of shattering the drum.


This isn't the race forum and no asked about picking up a tenth.


True, but he’s running headers so he probably isn’t a restoration/date code/part number guy. If he has nothing on hand there is no reason to run a 727, except if he cares that it might have come with one originally. Racing or not, do you want to run a less efficient transmission? More power to the wheels, better mileage, safer, comparable cost. Valuable info no matter what you are doing with the car.
agree
Posted By: poorboy

Re: Small block 727 brackets - 08/08/22 11:59 PM

Unless you are planning Dukes of Hazzard jumps, the small block will survive just fine without the extra support brackets. I ran a lot of SB Mopars with an auto on a dirt track, all without the extra brackets, and never had a single issue. I can almost promise you are not going to put your Dart through what those old dirt track cars went through.

As to the 904/727 deal. If both are box stock transmissions, the 727 will hold up much better under abuse then a 904 will. If the trans is being built, then the 904 can probably hang with a box stock 727, but if both are being built, the 727 is a very tough trans and can take a lot of abuse.
I tend to kill auto transmissions. Its 727s for me. I've killed way more 904 then I ever killed 727s, and I've had more 727s.

Of course, your mileage may differ.
Posted By: 6PAX

Re: Small block 727 brackets - 08/09/22 12:37 AM

Originally Posted by FurryStump
True, but he’s running headers so he probably isn’t a restoration/date code/part number guy. If he has nothing on hand there is no reason to run a 727, except if he cares that it might have come with one originally. Racing or not, do you want to run a less efficient transmission? More power to the wheels, better mileage, safer, comparable cost. Valuable info no matter what you are doing with the car.


Not a numbers car nor stock in appearance/build but it is an original 340 car so I would assume had it originally been an automatic it would have had a 727. I do already have a stock 727 I planned on using and I do plan on putting a shift kit in it. I don't think I'll bother with the brackets
Posted By: justinp61

Re: Small block 727 brackets - 08/09/22 12:23 PM

My car runs 10.0's with no braces or issues.
Posted By: JohnRR

Re: Small block 727 brackets - 08/09/22 01:29 PM

Originally Posted by 6PAX
Originally Posted by FurryStump
True, but he’s running headers so he probably isn’t a restoration/date code/part number guy. If he has nothing on hand there is no reason to run a 727, except if he cares that it might have come with one originally. Racing or not, do you want to run a less efficient transmission? More power to the wheels, better mileage, safer, comparable cost. Valuable info no matter what you are doing with the car.


Not a numbers car nor stock in appearance/build but it is an original 340 car so I would assume had it originally been an automatic it would have had a 727. I do already have a stock 727 I planned on using and I do plan on putting a shift kit in it. I don't think I'll bother with the brackets


You will have to spend $$$ to make it live behind the 340, unless it's a show poodle you are just driving on and off a trailer .
Posted By: FurryStump

Re: Small block 727 brackets - 08/09/22 03:31 PM

I think, all 340’s came with 727’s originally, but could be wrong. My 68 340 did. You have the 727 then it is probably the way to go. Doesn’t take anything really exotic to make a 904 live at a pretty serious power level, but as stated above, your mileage may vary. Two more things you need to address with a 904 than with a 727. Pump drive and high gear clock spring, (if you are going to spin it a bit) Billet servo’s? probably good idea for both, quality steels clutches?, both. Billet lever? Really depends on the valve body/line pressure. Sprag? Rebuilt 904 is good for most street car apps. 727? You want the best one you can get. Billet drum? Not really needed in 904. Good quality bands for both. If you really search for the best price, not much more than a comparable 727. If you are going through the transmission, the cost difference to fix the most common issues isn’t much more than a totally stock rebuild for either transmission.
Posted By: Sniper

Re: Small block 727 brackets - 08/09/22 06:35 PM

Originally Posted by FurryStump
Originally Posted by Sniper
Originally Posted by FurryStump
Unless you have the 727, I would go 904, it would need a different driveshaft than the 727, but I would not put a 727 behind a small block. I just changed from a 727 to a 904 and all said and done will have picked up 2.5 to 3 tenths. Now, I increased my flash rpm by 300, in the same dia converter. Both were PTC 9.5” converters. I also changed to the low gear set inside the 904. I also went aluminum for the driveshaft. So it is not just your typical 727 to 904 swap, but no more 727’s for me. Just not necessary. As an added benefit a much lower risk of shattering the drum.


This isn't the race forum and no asked about picking up a tenth.


True, but he’s running headers so he probably isn’t a restoration/date code/part number guy. If he has nothing on hand there is no reason to run a 727, except if he cares that it might have come with one originally. Racing or not, do you want to run a less efficient transmission? More power to the wheels, better mileage, safer, comparable cost. Valuable info no matter what you are doing with the car.


So what? The 727 is more than sufficient to handle a 340. The same cannot be said about a stock 904. Safer? Not stock it ain't. Comparable cost? Not finished it isn't. maybe a core to build is comparable in cost but a stock 727 is all that is needed to handle the load, a 904 needs lots of costly parts to do the same. To be honest, if I was going to make the mistake of putting an automatic in place of a stick it wouldn't be either the 727 or 904 varieties. I'd get one with an OD gear.
Posted By: 5thAve

Re: Small block 727 brackets - 08/09/22 07:48 PM

If it's for race and speed use a 904/998/999. If it's a cruiser with a 340 or 360 and you want durability use 727.
Posted By: 6PAX

Re: Small block 727 brackets - 08/09/22 08:06 PM

Originally Posted by 5thAve
If it's for race and speed use a 904/998/999. If it's a cruiser with a 340 or 360 and you want durability use 727.


This.
Posted By: crackedback

Re: Small block 727 brackets - 08/09/22 08:20 PM

727 safer than a 904... never seen a 904 explode behind a street engine. 727 and that front drum can be fun.

A decent 904 build will handle a street 340 fine. Plenty of 904's running around on the street behind 400+ inch SB's. Probably use the same driveshaft as the 4sdpeed to boot.

It's not 1970 anymore and the huge dollars to build a 904 to live is simply not the case. Decent clutches/band and a tf2... I'd love to see a list of all these expensive parts required to make a 904 live. Put an extra clutch in the drum running the thin variants, man that's expensive. LOL Doesn't need an expensive drum to make it safe either... Wanna make a 727 so it's safe, front drum instant $500 bill to the build, you can build a strong 904 for that number alone. BTDT on building 904's

Of course a 727 is a tougher trans to hurt, it's also got bigger parts/clutches in it. Also has other drawbacks as well.

Pick you parts, pay your money.
Posted By: FurryStump

Re: Small block 727 brackets - 08/10/22 08:15 PM

I rolled the sprag in my 727 and cracked the case. I run a low band apply valve body, which probably stop it from going boom. In addition to the low reverse drum being jammed stationary from the crushed rollers. Shifted into drive and it seemed slow to engage. Tried to get it to do it again, it wouldn’t. It just felt wrong. I heard it pop once, which was enough of a hint for me to pull it. Could have gone real bad. I had to press the low reverse drum out of the case. The 904 smaller drum diameter allows it to spin faster before it comes apart. The years of the 904 being see as weak are gone. Can you kill one? Sure! If the OP is not tied to the 727, he should look into a 904, he needn’t take my word for it. Search 904 vs 727 see what pops up. Just my experience.
Posted By: 5thAve

Re: Small block 727 brackets - 08/11/22 03:24 PM

you still have to go out of your way to build a 904 to take the extra abuse when a 727 in stock form already does it and at the end it still has smaller parts that are more prone to failure.
If speed isn't the game there's no good reason to use a 904. For a cruiser I'd take durability any day.
Posted By: J_BODY

Re: Small block 727 brackets - 08/13/22 01:56 AM

Originally Posted by crackedback
727 safer than a 904... never seen a 904 explode behind a street engine. 727 and that front drum can be fun.

A decent 904 build will handle a street 340 fine. Plenty of 904's running around on the street behind 400+ inch SB's. Probably use the same driveshaft as the 4sdpeed to boot.

It's not 1970 anymore and the huge dollars to build a 904 to live is simply not the case. Decent clutches/band and a tf2... I'd love to see a list of all these expensive parts required to make a 904 live. Put an extra clutch in the drum running the thin variants, man that's expensive. LOL Doesn't need an expensive drum to make it safe either... Wanna make a 727 so it's safe, front drum instant $500 bill to the build, you can build a strong 904 for that number alone. BTDT on building 904's

Of course a 727 is a tougher trans to hurt, it's also got bigger parts/clutches in it. Also has other drawbacks as well.

Pick you parts, pay your money.


FOR THE WIN!!

I put an amazingly simple 904 in my Duster 2 years ago. I was going to pull it at 60 passes and check things over,but we’re at 84 and counting. Been mid 1.2 in the 60 and best of 9.10. The ONLY jewelry in the whole build is the A&A front clutch spring pack, and the A500 pump gears. I LOVE the 904 behind a small block! Even in my “street days” my Mirada had a 904 behind the 340 that was in it.
Posted By: moparx

Re: Small block 727 brackets - 08/13/22 07:43 PM

what kind of differences did you find between the A500 and the 904 pump gears ?
beer
Posted By: crackedback

Re: Small block 727 brackets - 08/13/22 07:45 PM

Originally Posted by moparx
what kind of differences did you find between the A500 and the 904 pump gears ?
beer


IIRC

A500 uses the D Drive. No more cracked converter snouts
Posted By: moparx

Re: Small block 727 brackets - 08/13/22 08:26 PM

you may be correct. i forgot about that.
i picked up an A500 take-out at a dealer auction years ago, and it came with a converter.
that converter had the D-drive snout on it, so i tossed it, thinking it was for a front drive 604 transmission.
yeah, i know. i'm a dumazz. it has been proven MANY times over the years.......... spank laugh2
beer
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