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gear ratio differance 720 & d-21

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Have to assume you are running a KA motor? If so the B type isn't going to stand up to that kind of pounding, the C type has a far stronger case, larger bearings, shift rods and forks.


The gear ratios for the '84-'86 720 trannys are:


FS5W71B transmissions:


1st.... 3.321

2nd... 1.902

3rd.... 1.308

4th.... 1.000

5th.... 0.833 this tranny has the same ratios as the '84-'86 200sx



1st... 3.592

2nd... 2.057

3rd... 1.361

4th... 1.000

5th... 0.813 The 4X4 can be identified by it's not having a speedo drive in the tail stock.


I have found two references to FS5W71C ratios used with VG, CA and KA motors used in 240sx cars (could not find any trucks) and they were the same as the 720 2WD ratios. Hopefully you know what you are running in your D-21s.

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I know a guy that races a hardbody with a built KA24E and spooled ford 9" rear end. He goes through 2nd gear constantly...rebuild like every 2-3 races. Looks like he's going to sell the truck, though, since he's able to win in his current class as long as the truck holds up and he wants to step up classes.


What does this have to do with your thread? I don't know...it's almost midnight, consider it a free bump :)


Yeah, it's a hardbody underneath there...


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It's a z-2.4 in a 620 kc/86-94 tranny.Not sure about B or C type ? and are the speedocables also not in tailshaft on these 4x4 models. with this info i,ll know what i have. at the same time i,m trying to gain 2mph at top speed, there are 4 fords and 3 toyota's i must pass.


to thisismatt:

yeaaah thats a bad ass truck!!!

where do the performance parts come from like alum pulley's,distributor,cap and roter,

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I could describe what a B and C type look like but pictures are more fun:




The transmission in the fore ground is an FS5W71'C' the one further away is an FS5W71'B'. Note the shifter type differences. The C type is a more robust casting than the B type. The C type used with a KA motor will interchange with the Z series engines as the bolt pattern is the same. The C type is about 2 inches longer than the B.


If you are running an '86 and up it will be a C type. I would not advise using the B type with any serious power.

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