14blt swap

[mollyman]

I've got an 81 K10 Sub with an original, stock 12blt in the rear. If I buy a 14blt will it bolt rite in??? Spring perches, shock mounts, etc...? I know I will need a conversion u-joint (thanks to some info from all the friendly ck5 forum guys).

 

[4X4HIGH]

First off if you have an 81 with a 12 bolt it isn't factory. You will need a 14ff out of any 3/4 ton truck or suburban and it will bolt right in but you will need to have the spring top plates also as they are different because of the larger axle tube size. You might also have to play a game with e-brake cables depending on what year 14ff you find. Then just the conversion u-joint and you'll be set.

 

[mollyman]

Yes my 81 K10 Sub does have a 12blt and it is factory!!!! My uncle bought it brand new in 81 and just gave it to me about 6 months ago, so I know it came with the 12blt. I am sorry but you are mistaken.

 

[UseYourBlinker]

You could always just measure the 14b spring pads CTC and figure it out.Try the search.

 

[pvfjr]

There's no need for measurement. If he gets one from a 3/4 ton it will fit, if he gets one from a 1-ton he'll have to move the spring perches. The 1-tons had a narrower perch width, cause the spring hangers are set in closer to the frame. Puts less torsional stress on the frame rails under heavy loads.

 

[dremu]

Yes my 81 K10 Sub does have a 12blt and it is factory!!!! My uncle bought it brand new in 81 and just gave it to me about 6 months ago, so I know it came with the 12blt. I am sorry but you are mistaken.

Breathe, guy; Scott knows his stuff.

Looks like '81 was the crossover year, at least according to

http://coloradok5.com/specs.shtml

So an '81 could have either rear end.

And to the original question, a 3/4 ton 14BFF will drop in and a 1-ton won't. Searching woulda found you that too.

-- A

 

[mollyman]

Thanks for the info. And Scott does know his stuff, he has answered my posts before and been a big help.