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73-87 Chevy _ GMC Trucks => Engine/Drivetrain => Topic started by: cwest on May 24, 2014, 02:44:50 pm

Title: Drive shaft length and cross member placement for trans swap
Post by: cwest on May 24, 2014, 02:44:50 pm
I'm in the last few steps of a TH400/NP208 to SM465/NP208 swap with my 86' K20.  Do those two combos use the same drive shaft lengths and cross members holes?  I'm assuming they are the same because the transfer case to trans adapters for both combos are different lengths which I'm hoping is an accommodation for both set-ups to use the same drive shafts and cross member placement, but just thought I'd get some input from the forum.
Title: Re: Drive shaft length and cross member placement for trans swap
Post by: Dan75k20 on May 24, 2014, 05:04:34 pm
I switched to a np205 from a np 203 thus needing a longer driveshaft and am using a drive shaft from a stick shift truck it fits perfectly
Title: Re: Drive shaft length and cross member placement for trans swap
Post by: roundhouse on May 24, 2014, 07:14:39 pm
Measure the length from where the bell housing bolts to the engine to the rear driveshaft yoke on both setups
Title: Re: Drive shaft length and cross member placement for trans swap
Post by: bake74 on May 24, 2014, 11:54:02 pm
     No & NO.  The best and easiest way to me is go ahead and get the engine, trans, transfer case combo in.  Measure the cross member and re-drill and mount.  Measure drive shafts and have made or modify yours.
     See here (http://www.tciauto.com/tc/trans-dim/) for th400 dimensions.
     See here (http://www.novak-adapt.com/knowledge/sm465.htm) for SM465 dimensions.
Title: Re: Drive shaft length and cross member placement for trans swap
Post by: Irish_Alley on May 25, 2014, 03:40:11 am
keep in mind that sm465 dimension doesnt include the bell housing
Title: Re: Drive shaft length and cross member placement for trans swap
Post by: Dan75k20 on May 25, 2014, 12:08:04 pm
Bake is right I just got lucky that the th350 with a 203 and 205  cross members mount in the same place on a 75 and the drive shaft has a slip yoke built in

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