I forget which Buick stalwart told me this. It might have been Darwin Falk or one of the other old timers who have pulled a zillion engines from wrecks. Maybe even Sean Cahill. Whoever it was said he has found a few Stage engines and knows others that also have found Stage heads in their 70 Rivs. I know I even read it somewhere as well. I'll email Darwin tomorrow and see if he can tell me.
Buick Master Parts Cat. 3.91 = performance gear (#1396809) (65-70) 3.23 = trailer option (#1394290) (68-70) The acutual parts books show you could get a 2.78 (#13940850) for a 65-70 Riv. also. I am not saying it was factory listed option as sold new. I do not know.
The Shop Manual only lists the 3.07 and 3.42 as options. So, you're saying that the Master Parts Catalog would provide parts that the shop manual either isn't aware of or didn't list? I know that from the time these books are written until the time the cars are made can be a couple of years apart, so changes can happen. We are aware of one set of steeper gears for our rears that we hope will someday be used as a template for making them for the aftermarket. I forget the ratio, but it is steep. 4.11 comes to mind.
I got a 2.78 non posi in mine and another spare from a donor 70 3.07 was posi option 3.42 was performance posi option on GS
I do not know anything about Rivs except they are rolling artwork ahead of their time then and now. But yes the Parts books provide a number for the 2.78 through 3.91 gear sets listed above. I presume you guys have the 3.42 and 3.07 part numbers. I did not look to see if they came in a posi. I just looked for the gear sets (R&P numbers.) One interesting piece of trivia is that the 3.23 does not list as becoming available until 1968 as opposed to 65. Perhaps this is when the trailer option came onboard?
See, I was thinking I had more of a highway gear like a 2.78 in mine. But when I looked at the chart in the '70 Buick service manual last night, it only showed a 3.07 for the standard peg leg axle. And 3.42 for the posi.(And 3.07 too if I remember.) With special order ratios of 3.23 & 3.91. Dang! I should have brought it to work and scanned that chart!
3.91 posi? :Brow: Any non-posi Riv rear end from what I've ever seen was 3.07.........I know there was other possibilities, but to the best of my knowlege this was the most common ratio. Back in my younger days when these were plentiful in the yards......... I looked at a lot of these (in search of the ever elusive 3.91's :Brow: ) :bglasses:
Sounds like the standard rear axle was 3.07 and the factory option was 3.42, and a 66-70 Riv owner would have had to order any other gear set combinations from the dealer parts counter. I bet not many Riv owners would have been aware of other sets being available, and not many dealers would tell the Riv owners at new car purchase time that other rear axle ratios were available from the parts counter. And then there would be the expense of the changeover at the dealer. Sounds likely that very few were installed.
All those I listed were available in 6- 9000 series so I would approach it knowing that an Estate wagon is a 6000 series. Perhaps more variety would be found in that model than LeSabres, Rivs or Electras.
The current motor in my 70 is from a 70 Riv my sister had since it was 4 years old. Outside of the oil pan swap and replacing the plastic timing gear the motor has not been apart. Since the heads have never been off, I can't say what size the valves are except that this motor runs cirlces around the original GS 455 it replaced. This past Labor day at Englishtown on street tires it was doing 14.0's all day. It does have headers (closed at the time) and a 3.73 posi, so I know that helps. But I couldn't put the SP convertor in high stall or it would smoke the tires through 1st and shift to second with the tires still spinning. This motor has run 13.6 on worn sticky tires with the SP on. :laugh: All these times were run with the motor never going over 4,400 rpm. ou: The point here is that whatever Buick did to the Riviera motor in 70 it worked. Would love to know what size the valves are, but am not going to pull it apart for no reason. If it ain't broke, don't fix it. Mark
My first car was a '70 rivy :Brow: I had it in the early '90s at the hight of the ''5.0'' craze :sleep: It was RARE that any mustank could beat me on short runs, and none could match my top end :laugh: My dad said it was the most powerfull car he had ever driven, and he had owned four Electras, '67, '69, and two '70s o No: Ive been told for years that the '70 riv 455 was the same as the Electra 455 All I know is, that was one hell of a first car :3gears:
I found some interesting stuff in my 70 Buick Salesman's data book about rear axle ratios. The chart shows that the 3.91 ratio was available from the factory as a special car order on LeSabre 455, Wildcat, Electra 225, and Riviera/Riv GS. That ratio has a notation restricting it to non-air cars only, which would have made for few installations. It would be fun to see the production reports for 70 to see how many actually got ordered.
Carl-My eyeballs are having a little trouble reading the scan, but does that show a 2.5what? ratio on the 225 and then 2.78 on the Riv and Cat as the standard ratios!?
I also see 2.78 as the standard axle ratio. 3.91 ratio is certainly a rare option. I'm not sure I'd want it in a Buick for street use!
Sorry for the poor quality scan job. The dealer book has tiny print and I didn't want the file size to get too big. The best way I know to improve it is to save the pic to your hard drive, then zoom in. The book says the standard ratio for the 455 cars is 2.78, except for the Electra at 2.56 and the Riv GS at 3.42 posi. Another part of the book boasts lower axle ratios for those cars as a new for 70 feature. I bet the 455 made so much torque in 70 that Buick decided to lower the ratios.
