What's the easiest way to get a posi in my 1961 LeSabre? Would it be possible to swap in a Chevy rear end? (12 bolt, 14 bolt?) Or is there an OEM Buick option?
First year for posi in a Buick was 1959. The units will fit 1956 to 1962. The carriers fit the following gear ratios. Carrier 1 = 2.78, 3.07, 3.23 Carrier 2 = 3.36, 3.42, 3.58, 3.91, 4.45 Assuming you have 2.78, 3.07, or 3.23 gears you could buy this one and swap it into your center section with the gears you have: http://www.ebay.com/itm/1959-1960-B...7?fits=Make:Buick&hash=item5d517309ef&vxp=mtr
Hmm thanks for the info. I'm not sure what ratio it is, I'll have to figure that out first! 2.78 is really high is there any option for lower gears? Say somewhere around 3.73-4.10?
The most common ratios are probably 3.07 and 3.23. You might be able to find 3.36 gears, but anything else will be difficult to find. You can't use the 2.78 gears that come with the posi for sale because they are for a closed drive (torque tube) car, so you would need to use the gears that are currently in your car. 1961 was the first year for open drive in Buick's. Also see this post: http://www.v8buick.com/showthread.p...arts-interchange-Monzaz&p=2110102#post2110102
I've tried looking this up and nothing is very clear on it...what the heck does "torque tube" and open/closed drive cars mean???
Open drive shaft cars are probably what you are familiar with: a drive shaft with a U-joint at each end (you can watch the drive shaft spinning if you look underneath the car). In a torque tube rear end, all of this in enclosed in a solid tube that forms part of the rear suspension (locates the rear end). If you convert a torque tube rear end to an open drive rear end you have to fabricate a suspension component (like the trailing arms used in Chevy trucks) to replace the function performed by the torque tube. Because of the differences between the two, the ends of the pinion gear are different. If you look at the link I posted above, you can see pictures of a 1957-1960 pinion gear for closed drive and a 1961-1962 pinion gear for open drive. Look at the ends to see how they are different.
Sean, yep, you are correct. 3.07 and 3.23 were found in domestic 61's. 3.36 were export only 61's. 61's did come with a post rear, best ID'd by the tag on the filler hole that is stamped indicating to use LSD fluid only, if that's gone then you'd have to open it up to tell
I have a 61 3.23 posi third member (diff head) that I am considering selling. I was going to use it in my 56 Buick project but have changed plans. Only problem is that it is in New Zealand and shipping back to USA is horrendously expensive.
