is 500 a fair price for a body unrestored posi rear with 2.73 gears? I have original open rear and believe I have 3.42s as the car is a 70gs455 with a/c. on the unit for sale, I would need to upgrade the gears. hector
If your '70 GS455 has the original open rear end and an optional ratio wasn't ordered, it has 2.93 gears. If you want a similar ratio then the 2.73 posi would be a good choice at a good price. If, however, you want a performance gear like the 3.42 you would have to either get a new carrier or a spacer because the 3 series gear set will not directly fit into the 2 series carrier.
You also need to test the posi. A used and abused Buick posi is not very useful as the cones wear out and are usually not serviceable. You might be better off upgrading yours.
if the 2.73 is a 68-70 Buick 8.2 it will be costly to convert to more desirable gear ratios. $500 is more than i'd pay.
Only the Stage 1s came with 3.42 with A/C. Non Stage 1s were 2.93 with Turbo 400 with or without A/C.
the $500 posi rear is from a 69 Pontiac firebird. but seems like it would be more cost effective to convert mine. Is it simply buying 28 spline axle, eaton posi unit and new 3.42 grs and slapping it in? I don't race the car-its a daily driver weekender.
I think your $500 is best put towards building your factory rear with whatever gears you want, and a new posi carrier.
I'd be hunting a 71-72 Buick or olds abody 10 bolt. It is the 8.5" ring gear and parts are plentiful.
I read George N.'s article on the desirability of the 8.5 over my 8.2. While I prefer originality I am not completely adverse to upgrading. Curious to see how many would upgrade OEM 8.2 rear versus spending the money to get and likely build out an 8.5? Admitting my ignorance, will the conversion to posi be a bolt on proposition, i.e. DIY? or a complex master mechanic issue?
Depending on your power and use the 8.5 will take you pretty far. But since you are starting from scratch a built 9" will be nearly indestructible and can be had with even more part availability. But it ain't even close to original. Look up the moleary build thread. He bought one and I guess likes it. If money were no object that is what I would buy , but since it is my main restriction I have an 8.5 out of a 72 skylark that will get assembled one of these days. I have a set of 3.08 and 3.23 gears to use and will probably go with a 3.70 set when I do the 2004r. I do dream big. As far as can you do the setup. I couldn't say but I always figure if someone else can I can too. YouTube has plenty of bids and buying new tools I one of my favorite pass times .
Totally agree that a '71 & up 8.5" 10 bolt is your best bet for heavy duty if you want to stay with a GM rear end. If, on the other hand, you want to consider cost and convenience, the 8.2 unit in your GS will serve you well with a good rebuild if you're car is used primarily on the street. I have an 8.2 with 3.55 gears in my 455 GS with over 460 HP and it has served me well. I do enjoy spirited street use and an occasional trip to the track. However, I don't plan to put slicks or drag radials on my car so, the rear end won't get as much abuse as one that is frequently hammered on off the line with good traction.
I would check with TA or someone else to see if they have gears for your 8.2 in inventory. Otherwise, Fabcraft, who made the 3.42 and 3.64 gears a couple years ago, appears to be out of them. Figure aboutt $1200 for a posi, 3.42/3.64 gears and install kit(bearings/seals/shims, etc.). I ended up buying extra shims from ratech.com when installling mine.
