Will a Kingcab 5spd bolt-in to a 521?

[hessianben]

I've got a L20 and 5spd from a '79 620 Kingcab...

...that wants to go into a '71 521...

 

The wheelbase is obviously longer, so I'm wondering if:

 

1. I can use the 4spd driveshaft? (I don't know the difference in length between L-series 4 and 5 speeds)

 

2. I should get the Kingcab driveshaft cut down?

 

I know a few people here have done similar swaps... any tips would be appreciated!!

 

thanks

 

 

this is the 5 speed (the one in the truck is the stock L16 manual 4 speed)

 

[datzenmike]

1/ You can't use the 4spd driveshaft because the FS5W71B 5spd is about 5.5" longer than your stock 4spd.

 

2/ Both trucks use a two piece driveshaft. You won't be able to use the 521 front driveshaft because it is 1) too long, and 2) a flange output that will not mate to the 5spd. You may be able to exchange the front driveshaft from the 620 onto the 521. I would doubt you could use or will even need the rear 620 driveshaft. If the front doesn't fit, have it shortened.

 

You will have to modify the rear tranny mount.

 

You'll like the extra gear on the highway.

Edited March 11, 2009 by datzenmike

[hessianben]

1/ You can't use the 4spd driveshaft because the FS5W71B 5spd is about 5.5" longer than your stock 4spd.

 

2/ Both trucks use a two piece driveshaft. You won't be able to use the 521 front driveshaft because it is 1) too long, and 2) a flange output that will not mate to the 5spd. You may be able to exchange the front driveshaft from the 620 onto the 521. I would doubt you could use or will even need the rear 620 driveshaft. If the front doesn't fit, have it shortened.

 

You will have to modify the rear tranny mount.

 

You'll like the extra gear on the highway.

 

 

So, I can use the front half of the 620 shaft, and maybe mate it to the rear half of the 521 shaft... Or, use the entire rear end of the 620 to match the gearing... Still probably have to shorten the driveshaft... at least then all the flanges will match.

 

Anyone know a shop in SoCal who will weld a DS?