454 - turbo 400 automatic transmission, do I need to upgrade or do something?

1974 CHEVROLET 1500

45,000 MILES • 7.4L • V8 • 2WD • AUTOMATIC

FRANKCASTILLO

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Hi Ryan, I saw your videos on YouTube on the 454 built for your Camaro. Thank you for taking the time and explaining everything with so much detail. I am building my 454 just like yours for my 1974 c10 truck. I have a question for you and hope you can help me. It comes with a turbo 400 automatic transmission; do I need to upgrade or do something to the transmission and the rear axle/differential. Or will the stock transmission and axle/differential be fine?

Oct 10, 2022 at 1:17 PM

RYAN L

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Hey there!

First off thank you so much for watching the series!

So many people run their stock transmissions with their upgraded big blocks, and they do work. The problem is based on how long the transmission will work for and that is based on condition. TH400 are the beefer of the GM automatic transmissions, however. On the other hand, to is supremely easy to take the transmission out now and have it rebuilt and have even stronger parts subbed in while the engine is out. That is something you will have to decide on your own.

As far as the rear end goes, the truck differential you have now I'm going to assume is a 12 bolt. That is the differential most people put in their hot rod like I have on my car. In the future you can change out the gearing and put a limited slip in, but it should be able to handle the power on your build, no problem.

Thanks again for using 2CarPros!

Best,
Ryan

Oct 10, 2022 at 4:14 PM