02SierraDur

I just picked up an 89 runner with 390000 kms. I have been offered a rotten 81 pickup for free with 100000 kms. The rear end on my 89 is howling and am assuming it won't last much longer. My plan is to swap both axles from the 81 into the 89. I know the gear ratios aren't the same but had a couple questions. If I swap the axles keeping my stock transfer case and plan on running 33" tires with this sas what would my gear ratio be like? Also I have thought about swapping motors taking the head off the 81 into the 89 but I read the 81 has donut style pistons and it won't work. I can't swap motors because the 89 is registered and needs emission tests... I'd just like to verify this is correct? Any help would be appreciated. thanks

dropzone

iTrader: (6)

81 could have 3.90 or 4.10. Who knows what gears someone may have swapped into the truck in the last 30 years.
Rear axle is 1.5" narrower on each side and has smaller brakes. Best bet would be to swap thirds to your current axle.
Free truck- cool but things are gonna need to be gone through IMO.
SAS conversion is doable but do your research...

Dome not donut shaped pistons and the head is different.