400sb flex plate torque spec

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mjck5

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mark
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1986 k5 blazer
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k5
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400
hey everyone,
i had to replace my flex plate in my k5 with a 400sb and a 700r4 tranny, i cant find any reliable torque specs anywhere, anyone know what the flex plate and torque converter should be torqued to? and what size of gap should there be between flex plate and torque converter?
 
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xm20k

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Flex plate bolts 65 torque converter 35 both with thread locker.
 

xm20k

Runs on 93 octane, caffeine, and spite
Supporting Member
Joined
May 26, 2025
Posts
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Reaction score
2,854
Location
Girard, Ohio
First Name
David
Truck Year
78
Truck Model
c10
Engine Size
388
Almost forgot should be 1/8" between converter and flex plate with the converter fully seated in the front of the trans if there is say 3/16" you'll need to add a washer or shim to make up the 1/16" at each bolt so you only pull the converter forward (away from the trans) an 1/8" to contact the flex plate.
 

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