5 lug 1/2 ton to 8 lug 3/4 ton swap

[Jimmy Canuck]

I am building a 79 1/2 ton 2wd from a parted out 79 3/4 ton 2wd.
I want to use the 8 lug rear end and front, but am not sure how much of the suspension I will need to swap out as well. Will the 3/4 ton spindles bolt up to the 1/2 ton a-arms? Also, will the rear 3/4 ton springs bolt up to the 1/2 ton hangers. Everything is at stock height. I just want the new gm wheels that the new 3/4 tons have.

Also, are the frames on 1/2 tons and 3/4 tons the same? Both trucks had 350's originally.

[Big Blue]

I have almost the same question. Lets see if we can get an answer.
Mine is, I have a 78 blazer rolling frame.I just picked up a 81-350,3 speed,1 ton utility truck.I plan on using just the engine,cab and front clip. But I was wondering about the rear. Would it be a better rear then the original rear in the blazer. If better how much trouble would it be to switch over??

Thanks..

[u2slow]

The 3/4-ton arms use greased metal bushings instead of rubber. Swapping the whole front suspension (including the massive crossmeber) will work. I don't know if the larger 3/4-ton balljoints will fit the 1/2-ton arms.

The 3/4-ton axle will bolt in to the 1/2-ton.

The 1-ton axle has narrower spring perches and different shock mounts.

The leaf springs will swap so long as they're the same length... 52" and 56" springs were used. The longer springs are only longer on the back half, so you could cut the rivets and move the rear hanger if need be.

[Big Blue]

Thanks u2slow for responding, Would you know about the rear in the one ton being used in the 78 blazer?

[EricS76]

You can use the one ton axle, you just have to weld on new spring mounts in the proper places. You'll also need to change the driveshaft yoke because the u-joint will be a couple sizes bigger on the new axle. I'd try to get the whole driveshaft from the one ton too. If you've got a 2 piece driveshaft, the slip joint at the carrier bearing is the same size for 1/2 - 1 tons. Might be able to use the stock front shaft and the 1 ton rear shaft. I did the opposite when i put a SM465 in my truck. Used the 1 ton front shaft and stock rear shaft.

[Big Blue]

Thanks EricS76, I'll have everything from the one ton. I have a two peice drive shaft from another truck. Well see if it worth it, if not i'll put whats left up for sale.
What might be left is the rolling frame, 3 speed,rear, put it this way...all i'm using is the cab,engine,front clip rest of truck is for sale. Before anyone ask the bed is a utility box (READING) in bad shape.

[Jimmy Canuck]

Thanks for the heads up about the 3/4 ton swap.

[TRUCKGUY]

ok i was wanting to do the same i found me a nice set of 1/2ton springs for my 79 in jcwitney.....and i am wanting to get a 3/4 or 1 ton rear....you just sayed i have to cut for the 1ton but what about the 3/4ton will it bolt right in? the drives saft isnt much of a problem seeing that i got the trans out of a 3/4ton pickup i can get a saft made for it....will it bolt right in other wise?.............


Thank's