84k5 to 78k10 swap

[88trailblazer]

Okay, I've got a 78k10 short bed with a 350 that just leaked a qt of oil after 4 days of no use, a t350 that also leaks but shifts fine and 203 that only works in HI LOC and LO LOC.

I found someone selling an 84 k5 with a "runs good" 350, possibly a 700r4 (he says it has overdrive) and what I would assume is a working 208. He wants $995 for the hole truck which my brother and I would also pull other parts from. After which we would part out the rest.

1st - 203 Vs 208? Which is better or at least which one sucks less? I believe the 208 is part time and I hate the 203 shifters.

2nd - How hard would the swap be from one rig to the other? Is there anything that I should worry about or plan ahead for? Will the driveshafts work?

I'm sure I'll have more questions, but this is a good start.

 

[88trailblazer]

Come on guys and gals, I'm sure I'm not the first person to think about doing this swap. I searched through the old posts and I found alot comparing the 208 to the 205, but none comparing the 203 to the 208.

I'm going to see the truck this weekend so I have to decide quick.

Thanks - Alex

 

[Muddytazz]

Yes the 208 is a part time case and is chain driven just like the 203.

As fas as the swap, what are you wanting to swap, the drivetrain or the body? Kind of hard to tell from your post.

 

[88trailblazer]

I'm looking at swapping the motor, trans, t-case, and driveshafts. I just can't afford to rebuild my current 350 and buy a 700r4 at the same time (this is a daily driver). Also this way I can finally get rid of that 208 for a part-time t-case.

 

[Muddytazz]

Yes, if your swapping the motor/tranny/tcase/driveshafts, all will fit. Bout the only thing you might need is a rear coversion u-joint cause I can't remember if a 12bolt and 10bolt ujoint are the same.

 

[88trailblazer]

Would I be able to use the blazer crossmember on the pickup? I think the 700r4/208 como is a few inches longer than the t350/203 combo.

 

[Muddytazz]

yeah, you MIGHT have to drill a mounting hole or 2 but it will physically fit yes.

 

[88trailblazer]

Sweet. I'll drive it this weekend and hopefully its actually in good shape. Thanks for the info

 

[pvfjr]

My 12 bolt in my 78 K10 used 1310 u-joints, should be the same as a 10 bolt. Unless your 10-bolt has those 3R or S44 joints. Drive shafts are probably gonna be different lengths though. You might be able to use your old rear shaft depending on drivetrain length differences. The new front shaft should fit into the 78 with no problems though. The new rear shaft probably won't though, cause the K5 has a different wheel base.

Edit: Just remembered that the 208 driveshaft is gonna be for a slip yoke transfer case. So you have to use the new one, and you'll probaly have to get it lengthened. Will be about $100 unless you can find one from a K10...

 

[pauly383]

I have never seen a 10 bolt from the factory with a 1310 yoke in the rear . I have had my share here in the yard and they were all that s44 joint .

I like the 208 for its low range , and its easy shifting . Keep in mind though that a truck that old may need the fork pads , or the whole range fork replaced if its been used a lot . I would at least try the case first before you buy it to see if theres any kind of grinding or binding before you cough up the duckets for it .

 

[88trailblazer]

I will have to compare the driveshaft lenghts this weekend. By looking at the truck I don't thinck the 4wd has been used to much. So hopefully I won't have to do any work to the t-case.