4x4 Drivetrain Swap

[68,69 K20]

I have a 69 K20 with a 6cyl, 4spd, t-221 rockwell, I leaning towards buying a buddy's 71 K5 mostly for the drivetrain and some other parts. The blazer has 350, 4spd, 205. I want to swap this combo into the K20. Can I use the stock driveshafts from the truck? I am hoping this swap is as close to bolt in as possible. Any problems or advice is appricated, Thanks, Mike.

[1969k10stepside]

You can swap the whole drivetrain..Use the motor crossmember from the Blazer and move it to a more forward location in the truck chassis as I believe 6 cylinders have the motor crossmember in a different spot.You might be able to use the current 6 cylinder crossmember if it's a 250,don't know.If its a 292 it's a totally different style crossmember.You will also have to move the t-case crossmember and torque mount backward since the SM465/NP205 is longer than a SM465/Rockwell T221 t-case combo.The front driveshaft from the Rockwell will be too short (Especially if you lift it),so use the one from the blazer.The rear driveshaft will obviously be different.The rear output is higher on a NP205 than a Rockwell so you will need a longer driveshaft.Your truck probably has a carrier bearing on the rear driveshaft doesn't it? When swapping in the NP205 you can eliminate that,but will need a longer driveshaft.You could buy one from a K10 or K20 to use or lengthen the one from the blazer.There was one from a 72 K20 somewhere on the East Coast awhile back..New Jersey I believe.The trucks with the NP205 didn't have a carrier bearing d-shaft..You could also use the front axle and get disc brakes if it hasn't already been swapped.You just have to switch the outer stuff on the axle to 8 lug.

[68,69 K20]

The truck was orig a 292, when I looked at the numbers on the motor is was a 250. As far as the carrier bearing goes I know my 68 K20 has one, it still has orig d-train. I haven't looked at the 69 in a while I don't remember seeing one on it. I am pretty sure it's a rockwell in the 69 as it has the same shifter as the rockwell in the 68. The truck is currently at my fathers, I am going there today or tommorow and will check the 69 for carrier bearing. Sounds like a straight forward swap, thanks, and I will report back about the carrier bearing. Mike.

[68K20 x Drill]

/for my rear driveshaft, I used the 1 piece shaft from my 73-87 donor truck and shortened it a few inches. I did it on my friends lathe, and it cost me nothing. I also had to notch the crossmember just behind the transfer case.