727 Build for Mid-10s

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mopowers

mopowers

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As the title suggests, I'm beginning to gather parts for a 727 build for my street strip 66 Dart. The engine will be a 470-512 low deck stroker (undecided on CI), but shooting for 600-650 hp. The car will run mid-10s in street trim.

So far, I'm considering a reverse manual valve body w/ LBA, bolt in sprag, billet rear servo, blocking 'load control' hole on front servo, 4.2 kickdown lever, w/ hd band strut, accumulator blocker rod, rebuild kit with new clutches, steels, and bands.

My question is, what parts would you upgrade in the 727, if any, for this type of build, or any other modifications would you make? I realize a stock 727 may work fine for some time, but I'd like to build it once and know it'll last with no issues.

Thanks!
 
You have a great parts list there, missing one thing. Billet drum. I know, they're expensive. Kills me how many people think a bolt in sprag and LBA valve body will "fix it" so the stock drum "won't explode". They are good safety measures for sure, but, in the end, what is the very last thing to fail? Your lower extremeties(sp) will thank you for it! With that being said, I ran a stock drum 727 for YEARS! with no failure. Burnouts starting in second. Once the tires are spinning, directly to third. That big block is going to make a **** ton of torque, good thing it's a light car.
 
The front clutch drum should be changed out to a race unit, and you need to factor in a good shield regardless of the sanctioning body requierments. I was thinking you are gonna end up with a $4500 trans, plus converter.
 
Stock with a manual valve body and converter of your choice. Was this a trick question?
 
Since money is no object. Lose the flex bands. You can use a kevlar lined band at the rear but I would not for the front one. I use a red alto up front. Go with the billet drum as mentioned. Thin Red eagle or alto linings with kolene steels and forged servo pistons. A CRT front pump.
More than happy to help you.
 
I't sbeen a long time since I ordered parts for a 727 but 2 things are for certain, get a manual valve body (reverse valve body if you run a factory shifter) and get a custom convertor built specifically for your engine/car combo.
 
Jadaharabi said:
How much can you spend on the tranny and how much on a converter?
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Honestly, I just want to buy parts that are necessary for my application. Luckily, I can afford any parts necessary to build a transmission for this application.

I do plan on getting a good convertor from Dynamic. I've had good luck with them in the past.

408 swinger said:
You have a great parts list there, missing one thing. Billet drum. I know, they're expensive. Kills me how many people think a bolt in sprag and LBA valve body will "fix it" so the stock drum "won't explode". They are good safety measures for sure, but, in the end, what is the very last thing to fail? Your lower extremeties(sp) will thank you for it! With that being said, I ran a stock drum 727 for YEARS! with no failure. Burnouts starting in second. Once the tires are spinning, directly to third. That big block is going to make a **** ton of torque, good thing it's a light car.
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I'm considering a billet drum as well. It's only money, right?

thesiren74 said:
Just talk to John cope at Cope racing transmissions, you can buy a complete trans.
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I will not buy a complete trans for a couple reasons. 1- I've never built one and I'd like to learn. 2- After reading multiple books, watching videos, and disassembling mine, I've realize how simple the TF's are. I have spoken with John and have a list of parts he recommends. I'm just doing some additional research to see what other opinions are out there.

Jadaharabi said:
Since money is no object. Lose the flex bands. You can use a kevlar lined band at the rear but I would not for the front one. I use a red alto up front. Go with the billet drum as mentioned. Thin Red eagle or alto linings with kolene steels and forged servo pistons. A CRT front pump.
More than happy to help you.
Click to expand...

The trans I tore down already has rigid bands and they seem to be in good shape. Is it worth re-using them?

Question about servos- I have a 68 727, which originally came with the more desirable non-'load-controlled' front servo. Unfortunately, I pilfered it to use in another transmission a while back and swapped it for the later 'load-controlled' version. Is it worth simply plugging the hole in the piston with a set screw, or should I be looking for another front servo?

roccodart440 said:
I't sbeen a long time since I ordered parts for a 727 but 2 things are for certain, get a manual valve body (reverse valve body if you run a factory shifter) and get a custom convertor built specifically for your engine/car combo.
Click to expand...

I definitely intend to get both.
 
mopowers said:
As the title suggests, I'm beginning to gather parts for a 727 build for my street strip 66 Dart. The engine will be a 470-512 low deck stroker (undecided on CI), but shooting for 600-650 hp. The car will run mid-10s in street trim.

So far, I'm considering a reverse manual valve body w/ LBA, bolt in sprag, billet rear servo, blocking 'load control' hole on front servo, 4.2 kickdown lever, w/ hd band strut, accumulator blocker rod, rebuild kit with new clutches, steels, and bands.

My question is, what parts would you upgrade in the 727, if any, for this type of build, or any other modifications would you make? I realize a stock 727 may work fine for some time, but I'd like to build it once and know it'll last with no issues.

Thanks!
Click to expand...
check out the 727 build thread @younggun2.0 did for his 470.
 
brian6pac said:
Invest in a blanket
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I failed to mention, I do have a new lofgren blanket that I will use.

oldkimmer said:
Just use some washers to block the servo. U will see what I mean when u dissemble it. But best to get a billet 1. Kim
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Thanks Kim. I was hoping you would reply. I will definitely look into that.

If my trans originally came with the two-spring front servo, and all I have is a later one spring load-control servo, would be okay to just plug the hole with a set screw, or would it be best to replace the servo?

Any thought on a steel front planetary? My trans has a 3-pinion front planet (in good shape) and the gentleman at A&A cautioned me against using that in my build due to the risk of stripping the aluminum splines.

What are the limitations of the stock input shaft?
 
I have never stripped a planetary. I like to put a 4 pinion front and rear. Servo u can modify. There is a factory HD input shaft in 440 6 pac cars and Hemi cars. They have a dallop of yellow paint on the splined end. My buddies 71 bee at 4100 pounds has never stripped a planetary or broke an input shaft. He runs a trans brake. 840hp and 780tq. Kim
 
oldkimmer said:
I have never stripped a planetary. I like to put a 4 pinion front and rear. Servo u can modify. There is a factory HD input shaft in 440 6 pac cars and Hemi cars. They have a dallop of yellow paint on the splined end. My buddies 71 bee at 4100 pounds has never stripped a planetary or broke an input shaft. He runs a trans brake. 840hp and 780tq. Kim
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Great info. Thank you!
 
mopowers said:
What are the limitations of the stock input shaft?
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I think I read that both input and output shaft are safely rated at 600hp, which is obviously a good but more that the factory ever wanted out of them. You already know I'm sure that many racers have exceeded that number, and I'm sure some by far without problems. You also know racing is dangerous, and risks go up, along with horsepower. I'd bet a lot of people have pushed the limit beyond 600 hp, and I'm sure my own 10.0 car has the stock shafts in it still as well. But, if it's only money lol......
 
make sure you get a new front pump gear set. either 1 one with the wider tangs or get the one with 2 flat spots similar to the front wheel drive pump set. as you are getting a new converter anyway. we use the wider pump gear and have never had a problem with it. plug the hole in the front pump and move vent to tail housing. we had trouble with front pump seal leaking several times after 1st stroker motor, so we found that the crank was a little too long. we used a midplate trimmed to bellhousing and never have had a problem again. use the later good transmission pan gasket for leak proof trans pan.
 
Lefty71 said:
I think I read that both input and output shaft are safely rated at 600hp, which is obviously a good but more that the factory ever wanted out of them. You already know I'm sure that many racers have exceeded that number, and I'm sure some by far without problems. You also know racing is dangerous, and risks go up, along with horsepower. I'd bet a lot of people have pushed the limit beyond 600 hp, and I'm sure my own 10.0 car has the stock shafts in it still as well. But, if it's only money lol......
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What parts do you have in the transmission in your 10.0 car?
 
rbkt65 said:
make sure you get a new front pump gear set. either 1 one with the wider tangs or get the one with 2 flat spots similar to the front wheel drive pump set. as you are getting a new converter anyway. we use the wider pump gear and have never had a problem with it. plug the hole in the front pump and move vent to tail housing. we had trouble with front pump seal leaking several times after 1st stroker motor, so we found that the crank was a little too long. we used a midplate trimmed to bellhousing and never have had a problem again. use the later good transmission pan gasket for leak proof trans pan.
Click to expand...

Thanks for the info on the pump gears. Are those really a weak point? I've never heard of those breaking.

How was the original vent leaking? On deceleration on the top end?
 
usually vent leaks in water box as you are heating tires and fluid is thrown around like in a storm. relocate it to tail housing slightly behind mating surface of case to t/shaft. we broken more than one set of pump gears, usually on decel on top end. we broke several frt planetaries due to our own ignorance. try this some time. grab a planetary from your pile and put it on an output shaft to check for sideways movement. if no movement it is okay. if you find one that has a lot of sideways movement, you probably have one that has a different spline degree. what we did is we tore down lots of trannys for spare parts and did not realize the difference in output shaft pitch. you may also find one that will not fit the output shaft as it seams too small. just difference in spline degrees.
 
Post #7 next to last line. "A CRT front pump." I believe John drills out the passages and installs new gears.
Plugging the vent hole behind the torque converter in the front pump housing is purty much a given on a 904 & 727. If you don't you may be chasing a leaking front seal that is not leaking.
 
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