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th-350 to 400

 
Shrike
V-6 Camaros rule!
Posts: 28
Joined: 03/12
Posted: 11/14/12 08:27 AM

Guys       I`v got a `66 Nova and just lost my 350. I`ve got too much hp and torgue for it. Want to change it out to a 400 I need to know ALL the differences. I know about the crossmember and the shorter driveshaft, but what about the kickdown cable and the dipstick. Using an neighbors lift (he has 3 race cars and 2 business trucks) and dont want to tie him up, so I need all my ducks in a row.    Thanks   shriker  

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76Skylark
Big Block power for the win
Posts: 868
Joined: 12/11
Posted: 11/14/12 10:44 AM

the output shaft is larger on the 400, there are different length tail shaft's for each type so a long 350 and a short 400 will mean a new longer drive shaft.350 can be built for a LOT of HP, so if you broke one, without upgrades to the 400 you can break it too!but not likely the same part as they operate differently,dip stick comes out the same but what did the 400 come from/you may can use the 350 tube but measure dip stick length to be sure,with a new gasket because with it installed a leaky gasket sucks. 400 uses vacuum to downshift,try to find a metal tube that is made for the job as the ends are very small to affect the vacuum signal and get vacuum from the intake not carb,carb can be used but it's easier from the intake to get the correct signal.  

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pepsi1
I mow my lawn and find Chevys
Posts: 1718
Joined: 09/11
Posted: 11/14/12 04:35 PM

Call TCI and talk to Lowell Poff. He is the guru there. Don't worry about breaking things. Like Skylark said the 350 is strong if it has been modified. The TH-400 eats a little more Horse Power. Either way you should be Okay.

Bob  

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skyeking
I mow my lawn and find Chevys
Posts: 2738
Joined: 08/09
Posted: 11/14/12 08:53 PM

Hi there,
 The TH350 is not a lame duck IF you rebuild it PROPERLY.
 Either way you are up for some Real bread Rolls but
 do it right now and forget about changing what does
 not need the change. NOW'S the time for a heavy duty flex
 plate and a look at the starter motor works...
   Good luck and all the best to the Olde Codgers Too!!.  
skyeking

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Dave632
I mow my lawn and find Chevys
Posts: 2253
Joined: 07/08
Posted: 11/15/12 06:27 AM

There are companies out there that can make a 350 live with 1000+ hp so don't give up on it. A friend of mine had one behind a 540 with juice in a 2600 lb car and it lived.  
[[SUPPORT AMERICAN CARS, STOMP A RICE CAR TODAY.]]

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68scott385
I mow my lawn and find Chevys
Posts: 1994
Joined: 10/09
Posted: 11/15/12 07:22 AM

you can spend the money to build the 350 right

OR

you can spend the money to get & build a 400 right AND THEN spend the money to convert to the 400  
68scott385 68scott385 68scott385

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skyeking
I mow my lawn and find Chevys
Posts: 2738
Joined: 08/09
Posted: 11/15/12 03:53 PM

It's all about MONEY!!  
skyeking

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pepsi1
I mow my lawn and find Chevys
Posts: 1718
Joined: 09/11
Posted: 11/16/12 09:14 PM

Hi Guys:
I have a Pro-Comp roller rocker shaft set-up thats Brand New still in the box. For small block Chevy.
They are straight with NO OFFSET with 1.5 ratio rockers.They install easy if you have screw in studs.

We had used the same set-up for a mule engine that had 1600 pulls on the same Pro-Comp set-up. The engine failed as Crazy Dave my dyno guy started pulling oil from the engine to see when it would start making noise. We tested them before we started selling them to our customers. They ran without any problem. I believe Dave the dyno guy said he changed 22 cams in our mule. If anyone is interested please PM me. Thanks

Bob  

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