Want to change 727 over to turbo400

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67steve

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The 727 is slipping in 2nd and all thru 3rd.. I want to upgrade to a 400.. Any body here that have done this have any pointers on what and how ??? 3500lb street car with a 700hp 493 pump gas motor. Looking to shoot 250 come spring.

I have spoke with some guys that have said they can make the 727 stay together up to a 1000hp for around $1500 bucks but all these 727 bomb pics got me a little scared.

Any thoughts/opinions are welcome,thanks.
 
Any transmission can grenade if you put 1000 hp through it. I personally don't think the 400 turbo is an upgrade at all. It has allot more moving parts to break. I can tell you that if you want a 727 to stand up to 1000 hp you'll probably spend $1500 or more on it but by the same token if you want to switch to a turbo 400 you'll spend allot swapping over to it and in stock form it will come nowhere close to holding 1000 hp so figure on spending at least $1500 to build it. As far as exploding 727's go. I don't see very many explode. Yeah back in the 60's before torque converter technology was great they didn't have much stall so allot of guys did neutral drops and grenaded quite a few but that can kill any transmission. The Torqueflite has one weak area that allows this to happen. The rear sprague. Spend a few bucks upgrading to a bolt in super sprague and you won't have the problem.

BTW: Where have you seen all these bomb pictures? If your listening to the shivy guys you'll sure hear how Chrysler's are junk. Nobody likes getting outran more than a shivy guy.

Oh yeah if your running 1,000 hp you should be running a scatter shield on any transmission your running. At that hp level any can grenade.
 
Like Fishy says, what it comes down to is a simple FACT, built wrong both the 727 and 400 will explode with 1000HP going through them and it will cost you at least $1500 (probably more) on just the tranny to make it survive. You're also going to have to spent around $1000 for a top of the line converter because this now becomes the weak link and for the sake of your feet and legs invest heavily in a scatter shield.

JMO Terry
 
an upgrade to a turbo hydramatic 400 is the classic definition of a oxymoron. like a crying clown kinda thing. the above posters pretty much nailed it.
 
Read this and then you.ll know what you need to do. In the 60s they put 727s behind almost everything that wasnt stock at the drags. It was the trans of choice even behind chevy power. With a billet drum bolt in sprag and a reverse pattern valve body theyre virtually indestructible. For A Bodies Only Mopar Forum > Automotive Technical Forums > Transmission and Drivetrain Tech
Exploding Torqueflites this is the best trans info ive found
 
Once you start pushing big horsepower, I think that you are looking to upgrade any transmission that goes into it , including the th400. You can upgrade the front drum to a billet for peace of mind against an explosion and run a blanket also. You figure the money spent changing things like the shifter ,bell adaptor,output yoke etc. would buy a billet drum maybe a blanket too ,saw on moparts someone selling those SFI ones for around $150
 
nobody mentioned you will lose 50 lbs , if this is the same trans my uncle uses in his almost 600 hp 2 barrel (i dont know the class but it's small clay tracks)race car. is it also a four speed. it doesnt sound like a bad plan for the the right build.( this is a small block though).
 
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