Deadpurpledog Posted August 28, 2023 Share Posted August 28, 2023 Was it possible to order a 67 Riviera with posi yet not have GS option? Link to comment Share on other sites More sharing options...
RivNut Posted August 28, 2023 Share Posted August 28, 2023 Option code G1 - performance axle with positive traction differential. $47.37 3 Link to comment Share on other sites More sharing options...
EmTee Posted August 28, 2023 Share Posted August 28, 2023 Link to comment Share on other sites More sharing options...
JZRIV Posted August 30, 2023 Share Posted August 30, 2023 (edited) I've seen many 66/67s non GS with the 3:07 posi especially in snowbelt regions. I have never seen a non-GS with the 3.42 but as Ed stated it could be ordered. Most likely case to order back in the day would be if someone was planning towing a trailer. Unless one is driving in snow or mud or drag racing, posi's in these cars are highly overrated and unnecessary and more about bragging rights the way most of us driving classics today. I'd take an open diff 3.07 any day considering modern highway speeds! Edited August 30, 2023 by JZRIV (see edit history) 4 Link to comment Share on other sites More sharing options...
EmTee Posted August 30, 2023 Share Posted August 30, 2023 I remember my grandfather telling me that he specifically did NOT order a limited-slip diff in the new '69 LTD Country Squire he bought. His rationale (apparently based on experience) was that on slippery roads both rear wheels can break traction and before you know it you're facing 180° from where you started. With an open diff, if a rear wheel breaks traction no torque goes to the other wheel. Anyway, I agree with Jason. Besides, I think it's more fun (and easier on the tires) to get rolling at 10~15 mph then open the Q-jet... 1 Link to comment Share on other sites More sharing options...
telriv Posted August 30, 2023 Share Posted August 30, 2023 There was a guy by the name of John from upstate Ct. that had a '67 non GS that had a 3.42 posi as this is the way his grandad ordered the car. Tom T. 1 Link to comment Share on other sites More sharing options...
NC1968Riviera Posted October 1, 2023 Share Posted October 1, 2023 An owner of a 68 GS was talking about how his engine revs too high at hiway speeds because of the 3.42 rear end in his car. He says it nice for quick launches at the stop light but not so much for hiway driving. Link to comment Share on other sites More sharing options...
Deadpurpledog Posted October 2, 2023 Author Share Posted October 2, 2023 Isn't it difficult to imagine they would have knowingly built a "luxury" cruiser incapable of cruising at normal speeds? Sure it isn't something else? Link to comment Share on other sites More sharing options...
Hazdaz Posted October 2, 2023 Share Posted October 2, 2023 On 10/1/2023 at 3:44 PM, NC1968Riviera said: An owner of a 68 GS was talking about how his engine revs too high at hiway speeds because of the 3.42 rear end in his car. He says it nice for quick launches at the stop light but not so much for hiway driving. That sounds like his transmission wasn't getting out of 2nd. Or maybe even 1st. Maybe I am mucking up the math, but at 60 MPH, he should be spinning at only around 2000 RPM with 55R16 tires and a final drive of 3.42. It shouldn't be screaming, it should be just a few hundred RPM above idle at that speed. Link to comment Share on other sites More sharing options...
RivNut Posted October 2, 2023 Share Posted October 2, 2023 The RPMs that these engines turn are representative of the era. We're used to modern engines backed up by overdrive transmissions running us down the highway at 70 mph @ 2,000 RPMs. Just put on your 1960s hat and deal with it. 1 Link to comment Share on other sites More sharing options...
Rivdrivn Posted October 3, 2023 Share Posted October 3, 2023 I have a 3.42 posi with a 200R4 (auto 4 speed) from a 1987 Grand National. Quick off the line yet cruises easily at 80-100 on the highway. Best of both worlds! 2 Link to comment Share on other sites More sharing options...
RivNut Posted October 3, 2023 Share Posted October 3, 2023 Steve, That 200-4R is in your ‘69 GS, right? For those of you not familiar with the 200-4R, the overdrive is 0.67 % of the final drive. If your Riviera is turning 3,000 RPM @ 70 mph, then Steve’s engine is running at 2,000 RPMs at the same speed. I’m not saying the RPMs are correct for a 3.42 @ 70 mph but it’s good for an example. The 200-4R has a couple of advantages, 1) its smaller case means that no metal work is required on the transmission tunnel and 2) it is not a computer controlled transmission. The transmission works off a cable connected to your carburetor. Link to comment Share on other sites More sharing options...
steelman Posted October 3, 2023 Share Posted October 3, 2023 You want screaming, drive my 55 Chevy with a Turbo 400, 4.56 gears, and a G70x14 tire. Thought I would never get that car home. Love the car, but not one for a day trip. 1 Link to comment Share on other sites More sharing options...
RivNut Posted October 3, 2023 Share Posted October 3, 2023 I had a car like that some time ago. 55 two door post, 383 sb, TH400, and 4.11 gears. I know what you mean. Link to comment Share on other sites More sharing options...
NTX5467 Posted October 3, 2023 Share Posted October 3, 2023 Much of what might be deemed "revving too high" can be related to the sound of things, not just what we might perceive as "rpm". Exhaust sounds and related resonances can be a part of this, as can induction system sounds. One engine might be quieter at 3000rpm than another, for example. A 3.42 with modern tires is not too far off from a '55 Century (with tires from back then) with its stock 3.6 (or so) stock rear axle, as to mph/1000rpm. If a 3.07 ratio is "normal", with lower numbers being "highway/downhill gears" and higher numbers being "performance gears", so be it. End result is that the engines could spend hours at about 3000=3500rpm with no problems (other than an emptying gas tank), back then. The other side of the deal is that with a quieter exhaust system, if the engine sounds happy and little throttle input is needed on the highway, don't worry about it. Just enjoy! Just some thoughts, NTX5467 Link to comment Share on other sites More sharing options...
XframeFX Posted October 6, 2023 Share Posted October 6, 2023 On 8/30/2023 at 5:58 AM, EmTee said: Both rear wheels can break traction and before you know it you're facing 180° from where you started. With an open diff, if a rear wheel breaks traction no torque goes to the other wheel. Anyway, I agree with Jason. Me too, especially in my modern driver. I ordered my JL Wrangler w/o the DSA. Traction control works fine in 2WD and if slippery, switch it to 4X4. Also, I don't like the idea of having rear wheels locked when encountering black ice at hwy speeds. If reacting too late, lose control. On 10/2/2023 at 6:05 PM, Rivdrivn said: Quick off the line yet cruises easily at 80-100 on the highway. Best of both worlds! Sigh, I have a DynaSlow! On 10/3/2023 at 8:59 AM, NTX5467 said: Engines could spend hours at about 3000=3500rpm with no problems (other than an emptying gas tank) True and more so now with my '63. Changed tires that had a slightly larger OD than original standard 7.10-15 BIAS Ply to slightly smaller 225/70-15. MPG was bad, now worse I'm sure. On 10/3/2023 at 8:59 AM, NTX5467 said: One engine might be quieter at 3000rpm than another What engine noise? All seals are new but have yet to install Vent window rubber. Need to crack a window at hwy speeds to reduce the "racket". Typical 60s hardtop, with all side glass down, actually less noise. Side glass up, not a comfortable cruiser on the highway. Link to comment Share on other sites More sharing options...
NTX5467 Posted October 6, 2023 Share Posted October 6, 2023 11 minutes ago, XframeFX said: What engine noise? All seals are new but have yet to install Vent window rubber. Need to crack a window at hwy speeds to reduce the "racket". Typical 60s hardtop, with all side glass down, actually less noise. Side glass up, not a comfortable cruiser on the highway. My point is that trying to gauge engine rpm by how it sounds can lead to inaccuracies. What was once considered "normal" can lead to "over-revved" sounds now? As to weatherstrip issues, have you tried closing the side air vents, so the cabin is not pressurized at highway speeds? Using "Recirculate"/inside air on the a/c (if equipped)? It seems that every car, back then, had some level of "wind noise", just a matter of degree. Enjoy! NTX5467 1 Link to comment Share on other sites More sharing options...
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