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old school - installing a THM 400

Old 11-03-2012, 07:06 PM
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Default old school - installing a THM 400

Well guys, I am already old fashoned with my 4 barrel carb so I figured I'd get a turbo 400. All I need now is to ditch my Ipod and get an 8 track player!

I've spent much coin on 4L60s and 700s and they're just not surviving under my car. I'm going to get a 400 and beat on it and see if I can kill it behind this LQ9.

The car only weighs 3250-3350, but it hooks hard and has lots of torque.

I think my flexplate and spacer is going to work and I am pretty sure my crossmember and cooler lines will all work. I need a new yoke (and a driveshaft shop) and a converter.

please chime in if you've done a 400 behind an LSX

thanks
Old 11-07-2012, 04:31 AM
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here is what i ended up using..

take a look at post 54 and 55 of my build. i bought the hughes adapter that was supposed to be for the swap but what it ended up doing was holding the th400 convertor away from the flywheel so after some research i found that you can use this spacer, flexplate and longer bolts.

Originally Posted by FakeSnake
for reference if someone is doing a TH400 conversion and mating it to a 5.3 with a standard 400 convertor all you need is a flat flexplate and spacer like the one pictured above, easy as pie. they can be found in most 6.0L with the 4L80's
https://ls1tech.com/forums/conversio...-3-swap-2.html

Old 11-07-2012, 09:23 AM
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You either need a flat flexplate and the GM spacer (like the picture above), or a curved 4L60E style flexplate with the hughes adapter (can't guarantee that the holes will be the correct diameter with a th400).
Old 11-07-2012, 05:37 PM
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Originally Posted by slow67
You either need a flat flexplate and the GM spacer (like the picture above), or a curved 4L60E style flexplate with the hughes adapter (can't guarantee that the holes will be the correct diameter with a th400).
i tried the dished flexplate and hughes adapter with a factory style th400 convertor and the flexplate wasnt far enough off the back of the block to allow the the convertor to mate up... i cant find the pics i took of it but there was a good 1/4" of space bewtween the dished plate and the convertor pads


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