PDA

View Full Version : 1970 GS & GSX rear end gear ratio???



3lark
02-15-2006, 08:40 AM
What wat the factory gear ratio for the 1970 GS & GSX with a 455 & auto trans.

flynbuick
02-15-2006, 08:48 AM
What wat the factory gear ratio for the 1970 GS & GSX with a 455 & auto trans.

If AC --3.42 Buick 8.2

If non AC --3.64 Buick 8.2



If it was a GS made in Canada then it would be different. I believe all the X cars in 70 were made at the Flint plant.

Marco
02-15-2006, 10:25 AM
I know could be a little off base here because I'm at work and I don't have my documentation with me, but...

- The 1970 GSX had a standard gear ratio of 3.42:1, both TH400 and 4-speed, with or without A/C. If you purchased the stage1 option with your GSX, and you did not purchase A/C, you would get a 3.64:1 rear.

- The 1970 GS455 (non-stage) TH400 had a standard gear ratio of 2.93:1 (I *think* the 4-speed received a 3.23:1). The 3.42:1 could be purchased as an option, along with the 3.64:1/3.91:1 ratios (for non-A/C cars only).

I hope this information is correct :Comp:

WE1
02-15-2006, 10:48 AM
I've enlcosed a copy of the ratios available for 70.

Hope the sizing comes out so you can read it.

It shows the 455 cars with 3.42 std. with the manual trans.
350 GS cars with 3.23 with either trans.

flynbuick
02-15-2006, 10:50 AM
I know could be a little off base here because I'm at work and I don't have my documentation with me, but...

- The 1970 GSX had a standard gear ratio of 3.42:1, both TH400 and 4-speed, with or without A/C. If you purchased the stage1 option with your GSX, and you did not purchase A/C, you would get a 3.64:1 rear.

- The 1970 GS455 (non-stage) TH400 had a standard gear ratio of 2.93:1 (I *think* the 4-speed received a 3.08:1). The 3.42:1 could be purchased as an option, along with the 3.64:1/3.91:1 ratios (for non-A/C cars only).

I hope this information is correct :Comp:

Marco a 3.08 is not even a 70 8.2 ratio for US made cars. In 70 that was a ratio for 8.5 Canada cars and 9 3/8 inch rear boats like Rivs.

We owned a 4 speed 70 GS 455 non stage and it came with a 3.42. I do not think any of the rear ratios are GSX specific. They were GS specific and AC specific. They were all (US made ) either 3.42 or 3.64 unless otherwise specially ordered. ( Now I know someone has an open rear or other isolated example that we cannot explain.)

Marco
02-15-2006, 10:53 AM
Marco a 3.08 is not even a 70 8.2 ratio.

We owned a 4 speed 70 GS 455 non stage and it came with a 3.42.

:error:

Sorry, I meant 3.23:1.

According to the chart Dave posted above, the standard rear gear ratio for a 1970 GS455 4-speed was a 3.42:1

I was wrong either way on the GS455 4-speed standard ratio :Dou:

Marco
02-15-2006, 11:01 AM
The GSX was supposed to come with a 3.42:1 standard (probably because the 4-speed was standard and GS455 cars received the 3.42:1 rear)

Also, even though the GS455 4-speed cars got the 3.42:1 standard, I believe it was an open rear (non-posi).

Here's the GSX brochure -

<img src="http://www.v8buick.com/attachment.php?attachmentid=65004">

flynbuick
02-15-2006, 11:09 AM
3.23 is the a 70 GS 350 or wagon ratio.

The WE1(A9) codes for the GSX package incorporated , among others, the G1 code by reference which is code for positive traction. G2 was the non posi code.

We currently own just such a GSX car and it is right on the original window sticker. So GSX 70 cars came with posi traction unless specially ordered otherwise.

flynbuick
02-15-2006, 12:12 PM
Sorry Dave I just saw your chart up there. They are a little hard to read. I looked at the Factory Parts books I have and I agree that a 4 speed or a 3 speed manual GS 455 (Stage 1 or non stage 1) came with a 3.42 rear gear if it had AC. ( We owed just such a convert) I also looks like an auto TH 400 GS 455 non stage 1 would have a pc code rear which is a 2.93. What is not clear from the parts book is whether a GSX non stage 1, auto 70 car would nevertheless have a 3.42 because of the GSX option. So I went back to the assembly manual page 0-12.06 for the definition of G1 which is incorporated automatically into the GSX package regaerdless of whether it is a stage 1. It says that G1 means posi and the "performance axle" . Then going back to the parts book chart "performance" for a nonstage auto GS 455 is axle code "oo" which is a 3.42 ratio.

So the bottom line is that my interpretation is that a GSX came with 3.42 posi gears or 3.64 gears standard depending on how it was otherwise equiped. Is that you interpretation also?

Marco
02-15-2006, 12:19 PM
...So the bottom line is that my interpretation is that a GSX came with 3.42 posi gears or 3.64 gears standard depending on how it was otherwise equiped. Is that you interpretation also?

Yes.

I would be inclined to state all 1970 GSXs came with a 3.42:1 posi standard from Flint. If you ordered your GSX with the stage1 package, and did not order A/C, then your GSX would get a 3.64:1 as standard from the factory.

...although there is that 3.91:1 axle ratio that was available...

flynbuick
02-15-2006, 12:30 PM
Marco

You raise an interesting point that we debated earlier. The issue was that the factory chart in the parts book, and I think repeated by Dove's book, says that you needed a manual trans non AC , stage 1 car to get a standard ON code 3.64 rear. Dave corectly jumped in to point out that the factory book was incorrect and that auto trans stage 1 cars like that also had the ON. Since then I went on an investigation to confirm thisfo. It was on the same wavelength as Dennis Manner's comment at Flint in 2003 that the drop back to 3.42 in AC cars, stage 1, was to save the AC compressor from beginning spun so hard. Sure enough a member sent me a pic of his POP for an auto 70 stage 1 car and the ON code was embossed right in there. This confirmed what Dave already knew --the factory books are wrong in this respect and so is Dove's book.

3lark
02-15-2006, 02:00 PM
Thanks for all the feedback! :TU: I Will be dropping a 455 in my 70 Skylark and was looking to make at least the same power as the 70 Stage 1. I was thinking of going with the 3.73:1 gears but was unsure if that would be too much gear.

Poky1981
02-15-2006, 06:47 PM
Can someone tell me what the factory gear ratio is for 69 skylarks. And what is 8.2 & 8.5 for the novice car person. Thanks Michael