400 turbo

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400 turbo

Post by vht » Sun Apr 08, 2018 9:14 pm

What would you need to update on a 400 to say handle 700 HP, strip use with slicks and no transbrake? I know they recommend the 4L80 type direct drum with a 34 element sprag. I've researched some but seems like there is a whole bunch of opinions. It'll be converted to manual VB.

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Re: 400 turbo

Post by Coloradoracer » Tue Apr 17, 2018 6:38 am

Just pay attention to clearances and you'll be set. 36 element sprag is the only thing I'd worry about. A stock th400 can handle WAY more hp than you might think. Stock frictions and steels will also be fine. Might want to restrict the converter feed though, and perform the dual feed mod for the high clutch drum as well, but they are easy to do. A quick search on here should find you the information on those, it's been discussed here before.

Still my fav auto trans. Easy to work on and brutally strong!
Mark Goulette
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Speed kills but it's better than going slow!
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Re: 400 turbo

Post by af2 » Tue Apr 17, 2018 8:25 pm

Ron Sessions book is second to none on the 400. Very good illustration. I wish I had it when I built my first one.

I run a manual Valve body and leave at 6800 on the brake. Stock parts with good clutches and the 32 sprag has been good. Set the clutches to .050" and have fun.
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Post by dwilliams » Thu Apr 19, 2018 6:43 pm

Keep the stacks at minimum height. Sessions preferred paper clutches over the molded ones when he wrote the books; I've always followed his recommendation and stayed with paper, and never had any reason to regret it.

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