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#1
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I want to swap out a BOP 8.2 rear in my 1969 Firebird.
How much does the drive shaft need to be adjusted to swap to a GM 8.5 10 bolt or a 12 bolt rear. Does the trans type TH350 or TH400 make a difference on driveshaft length ?
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So then I said to myself "what would I do if I was me" ... |
#2
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I want to swap out a BOP 8.2 rear in my 1969 Firebird.
How much does the drive shaft need to be adjusted to swap to a GM 8.5 10 bolt or a 12 bolt rear. Does the trans type TH350 or TH400 make a difference on driveshaft length ?
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So then I said to myself "what would I do if I was me" ... |
#3
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Yes the th350,th400 makes a difference in length,not sure the exact numbers,also depends on the tailshaft length of both(various lengths there too).And the front yokes are different too,with several types for each.The rear ends I am not certain on,I do believe the 12 bolt uses a bigger u-joint in the rear than the 10 bolt generally.Length I don't know for sure.I would get the pieces in the car and measure to be certain what my needs are and go from there.Unless you have a shaft from a known combo to use for reference.Maybe someone will have that info here,we'll see.
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#4
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Get the car's full weight resting on the suspension on level ground. Put wood blocks under each tire to get it up high enough to crawl underneath it.
Push the trans yoke in all the way, then pull it out by 7/8". Measure the distance between the center of the front and rear U-joint cups. Then have the driveshaft shop make the shaft to your measurement. As mentioned by screamingchief there are many different yokes and there is no way to give an accurate number on driveshaft length. You must measure for the shaft length with the actual parts you're going to use.
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1964 Tempest Coupe LS3/4L70E/3.42 1964 Le Mans Convertible 421 HO/TH350/2.56 2002 WS6 Convertible LS1/4L60E/3.23 |
#5
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On mine, the only thing I was changing out and not reusing was my old 8.2 BOP rear end. I put in the new 8.5 corp. rear end and had to shorten my driveshaft by 1.125". As everyone said, there's some variation between different trans. and yokes, etc. so just take everything into account before you have it shortened.
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'72 Formula 455HO TH400, Revere Silver, black deluxe '74 Trans Am SD 4 speed, Admiralty Blue, blue deluxe |
#6
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The swap with a Turbo 400 would be anywhere from 7/8" to 1.125" shorter with a 8.5 rear, BUT measure it for sure
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http://www.stockappearingdrags.com http://www.stockappearingdrags.com Come on get off that lawn chair and drive that car like it was meant to be driven. 69' 400 RAIV Judge Conv... 12.86@107 Factory Stock 69' 400 RAIV Trans AM .....12.48@110 Factory Stock 69' 400 RAIV Judge HT..... 13.07@104 Factory Stock 73' 455 SD Trans AM........13's?? not run yet 66' 455 GTO Convert.........12.20@112 non original 63' 421 SD Catalina...........restored fast as h*ll |
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