727 HP Limits?

Posted By: keelsracing

727 HP Limits? - 01/10/10 02:58 AM

Biulding a "big bore" 440 stroker but what are the limits for the transmission.
And yes I know this really is not set but would like a-round-about number for HP and Torque.

Posted By: Anonymous

Re: 727 HP Limits? - 01/10/10 03:00 AM

i'm at 978 hp now with a 727 and no problems, going to try to run one with over 1200 hp in a few months.

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Attached picture 5724279-HEMIREUNION69HEMIRR65DODGECORONET002.JPG

Posted By: Mike Swann

Re: 727 HP Limits? - 01/10/10 03:23 AM

I get about 250 runs between rebuilds.

Posted By: montessa

Re: 727 HP Limits? - 01/10/10 04:10 AM

I am making 850HP at 3720lbs and haven't had any problems. Best 60ft at 1.34. Footbraking leaving at 1500 RPM's. Aluminum front drum, steel center pinion, rear bearing support and CRT reverse manual valve body. The only thing that has broken in the trans since switching to the automatic in 91' was the stock shaft. I can't remember if it was the output or input shaft. Pull the trans just about every year to be checked. Most of the time doesn't need anything. This year going to try a transbrake. I guess I'll find the weak spots now!

Posted By: beezer

Re: 727 HP Limits? - 01/10/10 04:38 AM

For many years funny cars ran 727's behind blown nitro motors making more power than most guys are making now without the good aftermarket parts that are available today.

Posted By: 340duster340

Re: 727 HP Limits? - 01/10/10 04:58 AM

sorry to hi-jack the thread, but what does it cost to build a 727 to handle high HP application?

Posted By: blownzoom440

Re: 727 HP Limits? - 01/10/10 01:17 PM

Quote:

sorry to hi-jack the thread, but what does it cost to build a 727 to handle high HP application?

just how much HP?
i have 2K+$ in mine without convertor.

Posted By: 440Jim

Re: 727 HP Limits? - 01/10/10 01:53 PM

Quote:

i'm at 978 hp now with a 727 and no problems, going to try to run one with over 1200 hp in a few months.

Now that is some power!

It would be a better question to ask what parts are recommended for the power desired by the original poster. So if he adds that (and application, weight) that would be more informative.

I love my 727, cheap and strong.

Posted By: joshking440

Re: 727 HP Limits? - 01/10/10 02:10 PM

Quote:

sorry to hi-jack the thread, but what does it cost to build a 727 to handle high HP application?

I bought one from the baddest 727 builder in the world (insert CRT logo here) with the intentions of trying to hold together 1300hp, it was in the 4,500 range with the transbrake, but i really wanted the piece of mind the first few times down the strip that i was going to be ok!

Posted By: FASTFISH420

Re: 727 HP Limits? - 01/10/10 02:17 PM

Joe Chrisman aka Tranzact has been running one for years in his 2000plus horsepower car with no troubles..

Posted By: JohnRR

Re: 727 HP Limits? - 01/10/10 04:05 PM

Torque is what kills them , not HP , that said the diesel world is runnng 1500-1800 ft lbs thru the 47RE which is just an OD version of the 727 ...

Posted By: dizuster

Re: 727 HP Limits? - 01/10/10 04:17 PM

Quote:

Torque is what kills them , not HP , that said the diesel world is runnng 1500-1800 ft lbs thru the 47RE which is just an OD version of the 727 ...

Yeah but not to be misleading...you can't make 1500 ft/lbs. on a stock 47/48RE... Not without billet input shafts, valve body, converter, etc...

The point is though, there are parts availible to make a 727 handle a lot of power/TQ.

Posted By: gregsdart

Re: 727 HP Limits? - 01/10/10 04:52 PM

As said earlier torque is the test. Monte Smith might chime in, as I recall he said he was snapping stock (?)output shafts at 1,000 hp on n2o. To me that sounds like over 1,000 ft lbs of torque at the range they run those motors?
I have the same shafts in mine that I started with back in 1980! I have progressed from 600 ft lbs to about 780 ft lbs torque.

Posted By: V10nacuda

Re: 727 HP Limits? - 01/13/10 01:37 AM

Quote:

i'm at 978 hp now with a 727 and no problems, going to try to run one with over 1200 hp in a few months.

I would also like to see what guys are running... But include the weight the car is racing at!!!!
Because I am in the same boat looking for up grades for 850hp & 750tq @ at least 3500+ with driver.

Posted By: midnight maniac

Re: 727 HP Limits? - 01/13/10 01:49 AM

I really hate to down the beloved 727. But they just cost to much to build to make them live. I run a TH400 that cost less than 1500 with a brake. It holds up to 917 hp 528 in a 3400lb Road Runner.

Posted By: Anonymous

Re: 727 HP Limits? - 01/13/10 02:03 AM

Quote:

Quote:

i'm at 978 hp now with a 727 and no problems, going to try to run one with over 1200 hp in a few months.

I would also like to see what guys are running... But include the weight the car is racing at!!!!
Because I am in the same boat looking for up grades for 850hp & 750tq @ at least 3500+ with driver.

3340 lbs with 4.56 gears, dana 60,ladder bar.
1.28 60 foot now. 835 foot lbs.torque,footbraking.all motor.

http://www.youtube.com/watch?v=g1Sn3zGG_aQ

http://www.youtube.com/watch?v=ApRw9pwDtMQ

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Attached picture 5730966-65dodgecoronetatatcohittintireshard.jpg

Posted By: JohnRR

Re: 727 HP Limits? - 01/13/10 02:41 AM

Quote:

Quote:

Torque is what kills them , not HP , that said the diesel world is runnng 1500-1800 ft lbs thru the 47RE which is just an OD version of the 727 ...

Yeah but not to be misleading...you can't make 1500 ft/lbs. on a stock 47/48RE... Not without billet input shafts, valve body, converter, etc...

The point is though, there are parts availible to make a 727 handle a lot of power/TQ.

I never said a stock one would handle that and I have to believe that those asking and replying to this thread are not ASSuMEing stock either .

Posted By: JohnRR

Re: 727 HP Limits? - 01/13/10 02:43 AM

Quote:

I really hate to down the beloved 727. But they just cost to much to build to make them live. I run a TH400 that cost less than 1500 with a brake. It holds up to 917 hp 528 in a 3400lb Road Runner.

Is that $1500 including adaptors and fabbing up a crossmember? Did you have to cut the Tbar X member ?

Posted By: midnight maniac

Re: 727 HP Limits? - 01/13/10 11:00 PM

No had another 350 in the adapter and flex plate. We just modified the orignal cross member. But still either way, still cheaper than a 727. Plus if the roller clutch decides to fail you just lose 2nd. gear, Not blow the tran, and possilbly the car to bits.

Posted By: Rapid588

Re: 727 HP Limits? - 01/13/10 11:55 PM

Don't kid yourself about T-400's and 350's not coming apart. If you have the stock cast drum in them just like the T-flite's that come apart, you will find out first hand what happens if you have a habit of dropping into neutral after the stripe like a lot of people like to do.

The engine slows down to an idle speed and stops or slows the input shaft, which allows the output shaft, which is connected solidly to the driveshaft, to spin the planetaries around 2.5 times output shaft speed into an overdrive mode, which could conceivably spin the direct CAST drum to well over 14,000 rpm which can .....well, you know the rest

No matter what trans you use, make sure you have a good shield as the girl in this Chevelle found out anything can happen (she did get hurt). http://www.youtube.com/watch?v=rNBMtV_NDfo

Posted By: dOc !

Re: 727 HP Limits? - 01/14/10 12:01 AM

Quote:

Torque is what kills them , not HP .....

...and the WEIGHT of the vehicle.

Posted By: hemi-itis

Re: 727 HP Limits? - 01/14/10 12:13 AM

Certain upgrades are needed,mine is a roller 727 with some goodies in it.My junk has 800 +fwhp and is treating me well thank to Tommy

Posted By: draginmopars

Re: 727 HP Limits? - 01/14/10 04:42 AM

Quote:

Quote:

Torque is what kills them , not HP .....

...and the WEIGHT of the vehicle.

also alignment to the crank helps it live longer.
seen more than a few with broken pumps/ TC
or convertor neck worn on one side.

Posted By: StripeHOG

Re: 727 HP Limits? - 01/14/10 05:38 AM

my old man's been running a stock T-flite w/ grinner brake for at least 10 years running 6.40's in the 1/8

I think he goes through it every other season.... My car has had the same tranny since 05 running 7.0's in the 1/8 probably 600-800 runs!!! 2nd gear burnout and not getting on and off the throttle in 1st gear contribute to the long life

Posted By: Al_Alguire

Re: 727 HP Limits? - 01/14/10 06:11 AM

I dont think it is a question of how much power they will take. I think it is more of a question of how much money is building one to last with X horsepower gonna cost me. now having said that I am quite sure there is a point of diminishing return here, are there better alternatives for the money kinda thing. I have seen TF's that are in excess of $7000 in Comp Cars. So it is all a matter of how much pain can your wallet take. With the right amount of money anything can be done.