Anyone running a th400 in their a body?

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junior636

junior636

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Once, if ever, I get my bell housing from j.w. I am getting ready to mock up my 496 in my 69 dart. For those of you that are running this set up I am wondering how much you had to fab the trans tunnel if any at all? I am asssuming the cross member will need removed or fabbed but did the tunnel need work too? I have a 496 and Coan turbo 400 pro brake tranny.
 
I did a 4L80E, but I would imagine a TH400 wouldn't be too much different. Yes, the tunnel requires modification as well as the crossmember. I hope you're running coil overs, because the cutting required on the crossmember really won't allow you to keep the torsion bars. I'll get some pics of the crossmember for you when I get a free minute.
 

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I'm curious why one would want to go through all this hassle to put a TH400 behind their Mopar engine? I'm by no means a purist but short of a powerglide it would seem the 727 is a great 3 speed transmission. Just curious.
 
The 727 cannot take as much power.
 
REally? What the 727 limit? I've never heard that.
 
Exactly, right now I'm going to be at about 700hp or so and hopefully in the next few years north of 1000hp, it would cost way more to build or buy a 727 to hold that power (that i would feel safe with).
 
roccodart440 said:
REally? What the 727 limit? I've never heard that.
Click to expand...

Perhaps I should put it this way.

Build a turbo 400 to withstand 1200 HP.

Now, build a 727 to withstand it.

Keep a running tab on how much each one costs and report back.
 
RustyRatRod said:
Perhaps I should put it this way.

Build a turbo 400 to withstand 1200 HP.

Now, build a 727 to withstand it.

Keep a running tab on how much each one costs and report back.
Click to expand...

I have a 727 that I run with 730 hp na then hit it with 175 hp of nitrous. Its on its third season took it apart, looks good so back together it goes. I have 2500 in my trans, how much do you have in your trans, floor and front end to make this work?
 
I don't have a dog in this hunt. I am merely pointing out what the vast majority of people run making that kind of power. It's a fact. It's either the turbo 400 or a glide.
 
I guess A&A trans and pro trans should just close there doors because its a fact you need a gm trans to go fast.lol
 
Don't get me wrong, I have a powerglide for my car and will put it in some day, but it wont be because my 727 cant handle the hp. A two speed just works better and is faster drag racing and that's what I do most with my street car.
 
What do the high hp ford guys run for a trans? Other than a PG.

I think it's clear why people run a glide.
 
67dartgtw9 said:
I guess A&A trans and pro trans should just close there doors because its a fact you need a gm trans to go fast.lol
Click to expand...

Stop being an idiot. I didn't say that. Some people like to keep money in their wallet rather than be brand loyal when it really means nothing.
 
That is a given when comparing chevy to mopar. You can, apples for apples, nearly, if not always build a chevy cheaper.

I ran a th400 then switched to a th350 and the car picked up 2 10th in the quarter 10.60 to 10.40, no juice.
I've seen chevy guys switching to the 904 lately using AMC/JEEP cases. They have been solid into 9 - 10's in the quarter.

My thinking here is simple and not a mopar / chevy thing. If you're going to make an engine to develop 1200 HP why would you then hamstring said engine of HP/ Q-ET by using a transmission that will do so. How much RWHP is sacrificed in this combo?

I am not "schooled" as I have been out of racing for some time but a simple observation and honest question.



RustyRatRod said:
Perhaps I should put it this way.
Build a turbo 400 to withstand 1200 HP.
Now, build a 727 to withstand it.
Keep a running tab on how much each one costs and report back.
Click to expand...
 
RustyRatRod said:
Stop being an idiot. I didn't say that. Some people like to keep money in their wallet rather than be brand loyal when it really means nothing.
Click to expand...

A conversion bell housing is 400, what do you want to say it cost to convert your car's floor boards and cross member? Let's say 300( I think that's a little on the cheap side). Ok now we have to buy a flex plate and spacer for the crank, about 250. Now I need to make new drive shaft 400. So now I have 1350 to get a Chevy trans to fit. You really think a 400 is that much cheaper to build at a 1200 hp level. You are kidding your self. My glide was 2500 dollars and I still have to spend money to get it in.
 
67dartgtw9 said:
A conversion bell housing is 400, what do you want to say it cost to convert your car's floor boards and cross member? Let's say 300( I think that's a little on the cheap side). Ok now we have to buy a flex plate and spacer for the crank, about 250. Now I need to make new drive shaft 400. So now I have 1350 to get a Chevy trans to fit. You really think a 400 is that much cheaper to build at a 1200 hp level. You are kidding your self. My glide was 2500 dollars and I still have to spend money to get it in.
Click to expand...

A bell housing is $330, if you have any talent at all working on cars the tunnel should be easy enough to fix. If you have a car making 1000hp are you going to use the stock driveshaft anyway? Im not sure what needs to be done with the flywheel yet but I do know you retain the stock starter. I paid $1000 for a th400 with a pro brake and billet drum, I couldnt touch a capable 727 for that. Hell, even Cope racing transmissions offers a bbm th400 on there site, its not like its un heard of to do this swap.
 
If I left the Mopar Camp, it would be a 2 speed.(Just my though) when your to the point of "light car and big HP"..... 2 speed is the way to go.
 
All I know is, the transmission shop where I worked specializes in Mopar. Those two guys have about 30 and 20 years experience, respectively. Rodney has a 5300 pound Grand Fury wagon that runs 12.80s in the 1320 and 8.40s in the 660. Stock stroke, 10:1 pump gas 440. He plans to upgrade to a stroker with nitrous and when he does he is going to build a turbo 400. When I asked why, he showed me. You can build a turbo 400 in the 1000-1200 HP range much more cheaply than a 727. In the end, the car doesn't know WTF kinda transmission it has, so what's the difference? I figure if two guys that build transmissions everyday agree on it, then there must be something to it. To argue from the standpoint "leave it all Mopar" is stupid when you are talking about a 4K dollar transmission VS a 2500 dollar one, unless you just like spending money for no reason. Yall are right though. The glide is probably best for a light car. Run whichever transmission you want. It's your car and your money.
 
Parasitic loss from popular transmissions. Specs from a old Car Craft test:

Powerglide_____18 hp
TH-350________36 hp
TH-400________44 hp
Ford_C-6______55-60 hp
Ford_C-4______28 hp
Ford_FMX______25 hp
Chrysler_A904__25 hp
Chrysler_727___45 hp
 
Don't 400's have a clutch pack engaged in all 3 gears? I thought the 4L80E's do. That would make them stronger than a band.
 
a full tilt 727 for my hotrod cost in the $9000 range. I have the convertors and flexplate. a powerglide cost in the $6000 range and I have to buy a convertor, flexplate, a shifter, cut the driveshaft, new front yoke, new cross member and an adaptor. so the cost will be a little less to about the same. at these prices and the parts in each they should be equal in horsepower output, strength and speed. there is no reason to even attempt to use a 400.
 
This thread alone proves why I hate to admitting to be a Mopar guy, of course im not closed minded like 95% of you...... I DONT WANT A TWO SPEED POWERGLIDE! How are you comparing a glide to a th400 there different. Thanks for keeping the thread on track, lots of very un useful information here....
 
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