Guest Posted February 18, 2002 Share Posted February 18, 2002 I have a question or two for you guys who really know the Riviera of the late 60's and early70's. On the new board that was started by J Wiese (v8buick.com) there is a section for the big cars and there has been a thread running about the differences and similalrity's of the ring and pinions and ratios available in that time. Pretty much everyone agrees that the 9 and 3/8 ring is one hard setup to find any information on. Also. seems like the lowest ratio is 3.42. There was also mention of an 8 and 7/8 ring in a 66 Wildcat. I'm pretty certain that the 67,8,9, and 70 were a 9 and 3/8 ring and pinion set up. One of the guys pulled a diff exchange between a pre 70 and a later axle and found that they would switch out but that the side gears or axles had deeper splines and was able to simply fit the splines and used it. <BR>#! Can anyone confirm when the 9 and 3/8 were first used.?? <BR>#2Can anyone tell me they ever saw a 3.91 in a 9 and 3/8??? <BR>#3Does anyone agree with me that there was a 3.91 offered in the Riviera in the late 60's or specifically in 1970??? From Flint!!! <BR>#4Was it possible that the 3.91 that was offered was still using the 8 and 7/8 diff?? <BR>As you can tell I'm trying real hard to find a lower rear for the 73 Will then add O/D and have best of two worlds. AND I DON'T WANT CHEVY OR FORD111 <BR>Thanks in advance for your input. Also, you should check out that new site Its good!! <BR>Ed Leaman Link to comment Share on other sites More sharing options...
NTX5467 Posted February 18, 2002 Share Posted February 18, 2002 I consulted my '68 Buick factory service manual and found the 3.07 and 3.42 ratios listed for the Riviera with other full size Buicks having 2.93 and 3.23 ratios listed. I seriously doubt you'll find anything "deeper" than the 3.42 for those cars in any year. The Skylarks/GS models would have had ratios up to about 4.30, but that was a different axle.<P>For what you mention, have you figured out just how much money you'll spend on the conversion and the how much allegedly better fuel economy you'll get from that investment (i.e., how long it'll take to justify the expense)?<P>Unless you happen to find the rare or GS vehicle that was ordered with the Performance Axle ratio, instead of the standard ratio, you'll end up in the aftermarket looking for gear sets (new ones). That situation alone could run over $500.00 installed. If you do find a used rear axle with the ratio you desire, it could well be junk. <P>Then, the transmission conversion costs of the transmission and brackets and such. Figure at least $1000.00 for that (using used/reman parts/transmission assembly). Considering incidentals, you're looking at about $2000.00+ to save how much money in fuel costs????<P>Then, there will be costs to get the speedometer gears recalibrated for the axle ratio and tire size.<P>Plus, having an "altered vehicle" that could very well have a decreased value due to these non-factory modifications. If you were dealing with something more common than a Riviera, it might be different.<P>It's one thing to have a "neat" vehicle, but another one to chunk money into a project that will have questionable results on many issues. You could do a whole lot worse than to just make sure what you've got is in optimum operating condition.<P>NTX5467 Link to comment Share on other sites More sharing options...
Guest Posted February 20, 2002 Share Posted February 20, 2002 You are absolutely right about the chances of recouping the expence. I guess I just want to make this big boat jump from the launch better! but I really like to drive it and want to be able to do this without turning 3000 rpm at 70 mph.I currently have a 3.42 rear under it with the posi. With the torque this thing makes road gears with 2000 rpm @ 75 would be great for the engine and for the milage and with the weight and the oversize rubber I'm running a 3.91 would be great for a launch. Besides its fun to hunt for something like this.Sure would like to know if the other GM cars in that era ran the same ring and pinion.<BR>Ed Link to comment Share on other sites More sharing options...
NTX5467 Posted February 21, 2002 Share Posted February 21, 2002 If you're going to search for something, it's better to search for something that's somewhat obtainable . . .<P>Operating on the premise that finding a deeper rear axle ratio is worse than finding the golden needle in the haystack, the next best thing would be the transmission. In this case, a BOP case Turbo700 from a middle '80s LeSabre. As the normal venue for that transmission in those cars was mated with a 307 Olds motor, it would need to be internally beefed up to handle the torque of the larger motor you have. Plus possibly some driveshaft alterations.<P>End result is a 3.07 low gear with a .69 OD ratio. With the newer fuel injection 350s, they handle that combination pretty well. The key to your Riv handling that lower cruise rpm will be the cam in it and how much torque it has in the 1500-2000rpm range.<P>It's possible that you might find a 2.74 low gear for the existing Turbo400 from the drag race transmission people. That might be the least invasive thing to do to get the added low end torque multiplication.<P>The other thing would be to retrofit a switch pitch torque converter and front pump into your existing trans. Instead of a torque multiplication factor of 2.1, the SP converter goes from a 2.6 to a 2.1 and can be toggle switched. This plus the deeper low gear could give you the extra jump you need without hurting the originality of the vehicle too much and might get real close to the low gear torque multiplication from the Turbo700 without all of the other changes to the car.<P>With the 3.42, or even a 3.91 ratio but to a lesser extent, the lower engine rpms at cruise might not be that good with a carburetor. In that case, an aftermarket Holley TBI system would do a better job of metering the fuel at the lower rpm, plus provide better throttle response during cruise. With the correct finesse, the Holley TBI can be hidden pretty well to not alter the cosmetic values of the original underhood area.<P>Just some additional thoughts.<P>NTX5467 Link to comment Share on other sites More sharing options...
Ted "Wildcat65" Nagel Posted February 21, 2002 Share Posted February 21, 2002 I have my '65 3.42:1 posi out of the car. It appears to be close to 10" dia, but do I measure the bolt circle or OD of the ring?<BR>Carmen Faso has told me the '66 is different, from housing to gears, but the suspension will bolt up the same (sorry, these are Wildcats-not sure on the Rivi's).<BR>For 65, there were some 3.91:1 (Bill Burton has these on his Wildcat 4-speed), and Bill also mentioned some other 4-somethings-seemed way out of the power band unless running some big tire combo... Link to comment Share on other sites More sharing options...
Guest Posted February 22, 2002 Share Posted February 22, 2002 70 riviera and electra came with 391 optional as did lesabre and wildcat<BR>All also came with 307 323 or 342 gear sets Link to comment Share on other sites More sharing options...
Guest Posted February 22, 2002 Share Posted February 22, 2002 Hey RUSS. I Like what you are saying about the 3.91 in 70! Can you come up with any part numbers or codes which would help find more out about these? I think we have figured out how to make a diff setup from a 70 work in a later rear housing! You guys should check out the big car forum on the new buick site <A HREF="http://www.v8buick.com" TARGET=_blank>www.v8buick.com</A> there has been quite a bit of interest in this subject and in figuring out what will interchange. Link to comment Share on other sites More sharing options...
Guest Posted February 23, 2002 Share Posted February 23, 2002 I'll have answer Saturday when I get back home.I do have part numbers there for the 391 gears.Any cars to my knowledge with the 364 or larger will be ac delete.I have been looking for years for a set of 391 to go in my Wildcat. Link to comment Share on other sites More sharing options...
Guest Posted February 23, 2002 Share Posted February 23, 2002 Maybe someone in Jacksonville Florida can help with the 70 Riviera gs you desire.<BR>Can't remember where but there is in a car parts yard a 70 riviera gs bucket seat interior fully loaded with original drivetrain looking for a new owner.It has the factory mags also. White/black interior.<BR>Wish I could be of more help on the car for you.<p>[ 02-22-2002: Message edited by: russ ] Link to comment Share on other sites More sharing options...
Guest Posted February 23, 2002 Share Posted February 23, 2002 I took some measurements on the rear parts from my posi 73 Riv rear with the 3.23 gears. this is what I can tell you for sure!!<BR>Ring gear inner dia. measures 6.004<BR>ring gear has 12 bolts to carrier bolts are.415 (7/16) outer dia on threads<BR>Ring gear outer dia. is 9.375 at widest about 1.60 thick<BR>Pinion overall lengeth is 8.495<BR>Gear on pinion is 4.685 largest dia.<BR>pinion Splines for yoke behind nut 1.285<BR>pinion,Small brg(front) 1.325 inner dia. rear brg 1.875 inner dia distance between pinion brg is 2.5 outside brg distance is 4.25<BR>casting # on posi carrier 761 (cast on both ends) also has a small 2 and 0E or CE on end opposite the ring gear. These measurements are close. Done with a caliper with needle guage. If anyone has any questions or measurements to compare with these please get a hold of me. <BR>PS cover on this rear is 12 bolt<BR>Thanks ED<P>[ 02-23-2002: Message edited by: Ed Leaman ]<p>[ 02-24-2002: Message edited by: Ed Leaman ] Link to comment Share on other sites More sharing options...
Guest Posted February 24, 2002 Share Posted February 24, 2002 Codes are for Riviera 323 PP 342 PY 391 PZ CODE is located if lucky on the left rear brake drum face if still original drum is on rear. If not there then there is a number located on bottom of axle tube left side. Link to comment Share on other sites More sharing options...
Guest Posted February 24, 2002 Share Posted February 24, 2002 Russ Do you know which years those codes apply to? and is there any chance the codes are used on any other chassis. As in wagons, or electra's ETC?<BR>Ed Link to comment Share on other sites More sharing options...
Guest Posted February 24, 2002 Share Posted February 24, 2002 Had to change the earlier measurements on the ring gear dia. Wasn't wearing my glasses.<BR>I beleive that they are close now.<BR>Ed Link to comment Share on other sites More sharing options...
Guest Posted March 1, 2002 Share Posted March 1, 2002 The only measurement that was needing corrected was the inner dia on the ring gear! It seems like some of the earlier rears have very similar measurements but I'm still needing more information! Especially would like to hear from someone with a 3.64 or a 3.91 that could be measured. I would like to get a price on having a set of gears cut or repopped. Probably not as costly a project as some other items because of the newer computerized machines. But i need something to start from!!! Link to comment Share on other sites More sharing options...
Guest Posted March 5, 2002 Share Posted March 5, 2002 Update on 9 and 3/8 rear parts!! Have received some measurements from several sources on different years of the big cars in the late 60's and the numbers are close. Will be trying to get a set of gears from a 67 to set beside my 73 set and do actual hands on comparison. We have pretty well proven that a 70 ring and pinion will interchange with the 71's and later years and we have proof that 3.91's were offered in 70 under a code PZ Also have a few people who would like to look into the cost of repopping 3.91's for the big rear.<BR>MR Wildcat 65, would you have time to measure your ring and pinion from your 3.42 and compare the measurements to the ones posted on the v8buick.com thread that we have had going over there??? If any one knows how to contact the OLds and Pontiac people there is credible evidence that this 9 and 3/8th gear was used both places. Was known as the severe duty or heavy duty rear.<BR>Thanks for all your help<BR>ED Link to comment Share on other sites More sharing options...
JUSTIN Posted March 5, 2002 Share Posted March 5, 2002 Didn't 65 Rivs all have the same rear end? What ratio was it? Is it positrac? Link to comment Share on other sites More sharing options...
Guest Posted March 5, 2002 Share Posted March 5, 2002 Codes to follow are 1970. May cover other years.<BR>Lesabre,smaller ring gear<BR>posis 273 no 293 nx,323 nt,342 nn,364 ny<BR>regul 273 nk 293 nj,323 nb<BR>estatewagon<BR>posi 278 pt 323 pu<BR>regu 278 pa<BR>wildcat,electra<BR>posi 256 pn 278 po 307 pv 323 pr 342pw,391px<BR>regu 256 pb 278 pl 307 pg <BR>riviera <BR>posi 307 pm 323 pp 342 py 391 pz<BR>regu 307 pj<BR>I know some cover 1969 as my 69 lesabre 293 posi rear is code nx.It is written in paint on left rear drum.Any car with origial rear drums will have a 2 letter code painted on left rear drum from factory.<BR>Hope this helps<BR>Russ Link to comment Share on other sites More sharing options...
Guest Posted March 6, 2002 Share Posted March 6, 2002 From Todd at buick.net posted reply<BR>GOOD infoEd, the parts lists give up some information relating to #3 in your message. Yes there was a 3.91 ratio Posi-Trac offered on the 70 Riviera as a trailering option. The 4/83 edition of the Buick parts list shows the ring and pinion set as a #1394093. The same part no. was used back to 63 on all full-size rear ends except the 65-70 LeSabre. There were other earlier part #s that this one superceded.<BR>This parts list covers cars up to 75 and shows no 3.91 ratio gear sets after 1970. There are some shown with ratios as big as 5.00 for the smaller body styles. <P>Not much is shown on the ring gear sizes though. There's a bit of data for the 71-75 ring gear dia, but nothing specific on the 70 or earlier. Some of the bearings do use the same part no. before and after 70. <P>There were 3.91 gear sets, Std and Posi-Trac, available on the 59-60 LeSabres with std. shift. This ratio was discontinued in 61 when Buick discontinued the std. transmissions on full size cars. The 3.91 appears to have returned in 62, maybe for the Wildcat as an optional ratio. Some Specials earlier than 59 used a 3.9 ratio on the std. shift cars, but these might not interchange with the 63-70 parts. There is one obscure reference in the speedometer driven gear parts list that shows a 4.45 rear axle ratio available on 64 full-size models. <P>Some of the shop manuals get vague on these trailering option ratios and refer to them as Special Car Order rear axles. The 66 and 68 manuals do show the 3.91 for the Rivieras in either standard or Posi-Trac. <P>IP: Logged<BR> <BR>All times are PT<BR> next newest topic | next oldest topic Link to comment Share on other sites More sharing options...
Guest Posted March 8, 2002 Share Posted March 8, 2002 alot of info on the v8buick.com site.<BR>Very interesting info on interchangability.<BR>Ed hope you can transfer this. I tried<P>Russ Link to comment Share on other sites More sharing options...
Guest Posted March 9, 2002 Share Posted March 9, 2002 Russ. I can bring it over but I wonder IF I should? It takes up a lot of room?? You guys should really check out <A HREF="http://www.v8buick.com" TARGET=_blank>www.v8buick.com</A> <BR>find the boatload of fun forum and the thread on 9 and 3/8 rears. But if You want just let me know what you want brought over and I will try to do it.<BR>ED Link to comment Share on other sites More sharing options...
Guest Posted March 10, 2002 Share Posted March 10, 2002 This is a copy and paste from a discussion going on in the buickperformance Digest.<BR>Thought it was interesting so here it is. more understandable if you read from the bottom up<P>Subject: Re: Part # for 9 and 3/8 ring and pinoin<P>Dave, I went to my garage & opened up the original box that these gears came in & on the ring gear it had the same number on it, also the receipt from 1968 from the dealer I bought the gears from had the same number on it. I can remember the parts guy & I going nuts trying to find a listing for the 4.45's. Every ratio was listed under the group # for all the other gear sets except for the 4.45s. Something to do with, I believe trailer towing or something. I do remember very clearly the parts man showing me a different part # for non posi, as he showed & pointed it out to me. I have never installed these gears as I felt that until I built something that would be able to pull up to 6500 RPMs it would be a waste. So I just opted to stick with the 3.90s & my stock 3.07 posi for cruising. I am at this time thinking of installing them to see if my times up to the 1000 foot mark will improve just as a test before I make & cast up a bellhousing for a 700r4 with the NailHead bolt pattern. Tom Telesco<BR> <BR>----- Original Message -----<BR>From: The Knutsens<BR>Sent: Friday, March 08, 2002 1:40 AM<BR>To: buickperformance@yahoogroups.com<BR>Subject: Re: [buickperformance] Part # for 9 and 3/8 ring and pinoin<BR> <BR>Tom:<BR> <BR>Nothing I have lists the 4.45 ratio part #, so that # you sent doesn't show up anywhere, but I do list all the other ratios for all series of cars. The gear sets are not different between posi & open. What is true though is that all the perf. ratios came standard with a posi. For the big cars that was any of the 3.90 and higher gearsets. For the 65 - 67 A body cars that was 3.36 for the auto. trans cars and 3.55 and higher for the stick cars. The 65 stick cars came with 3.36 standard so that was not listed as a perf. gearset, so posi was an option for that gear. The auto. trans cars came with 3.08 standard, so the 3.36 was the perf. gearset, so a posi. was standard in that application. Any of the A bodies in 65 - 67 the posi was standard in the 3.55 sets and higher numerically (3.73, 3.90, 4.30). Same thing applied to the 68 and newer A body cars, the perf. ratios varied quite a bit though. With the 3.42 sets and higher numerically also being posi only (even 3.23 in a few cases). All the optional ratios for the big cars were positraction.<BR> <BR>Dave Knutsen<BR>----- Original Message ----- <BR>From: Thomas Telesco <BR>To: buickperformance@yahoogroups.com <BR>Sent: Thursday, March 07, 2002 6:08 PM<BR>Subject: Re: [buickperformance] Part # for 9 and 3/8 ring and pinoin<P><BR>Since I have both the ratios mentioned for the older cars, 3.90 & 4.45, I can give you the # of the 4.45s as I have them out. The # for the posi gear set is 1351927. When I bought them in '68 I was told that the posi & non posi gears were different. Same for the 3,90s. <BR>Tom Telesco<BR>----- Original Message -----<BR>From: The Knutsens<BR>Sent: Thursday, March 07, 2002 4:53 PM<BR>To: buickperformance@yahoogroups.com<BR>Subject: Re: [buickperformance] Part # for 9 and 3/8 ring and pinoin<BR> <BR>Ed:<BR> <BR>I looked through two parts books, one 1976, the other 1979. They no longer listed the part number for the 4.45 ratio gears for the big car rearend (9 3/8"). They had a note to replace 4.45 gears with the 3.91 set when a replacement was necessary. The 76 catalog lists the 3.91 set as part # 1394088. The 79 catalog lists it as part # 1394093. These are probably the same #'s you already came up with. I thought I had some older parts books, but I can't locate them (maybe in the attic?) But I do remember the 4.45 ratio for the big cars. I have the numbers for the 4.30 (1396806) & 4.78 (1394307) ratios for the 8.2" rearends and the 5.00 (1394826) for the 8.5" rearends. They list the 3.91's starting in 1963 for the big cars. I also looked through several (4) history index books that list part #, warehouse #. list and retail price and dealer cost and dates that numbers were superseded, but since I don't know what the 4.45 ratio part # is it's not possible to look it up for sure, we can get close as the group # for the ring and pinion sets is 5.529. The oldest parts history books I have is dated 1970, then 72, 73 & 74. <BR> <BR>Dave Knutsen<BR>----- Original Message ----- <BR>From: lleaman@aol.com <BR>To: buickperformance@yahoogroups.com <BR>Sent: Thursday, March 07, 2002 4:00 AM<BR>Subject: [buickperformance] Part # for 9 and 3/8 ring and pinoin<P><BR>Does anyone in this group have a way to check out a GM part# for availability ? NEW OR USED!!! From a 1984 Parts book I was given a Part # wich supercedes a bunch of part#'s and basically will fit the big cars (Riv Electra etc) from 1970 back to 1963. It is for a 3.91 ratio ring and pinion. Also there is mention in the 1964 info of a 4.45 ratio.for the big cars but we didnot find a part #. Anyone ever heard of such a thing???. On the v8buick.com board there is more info about the codes and things for this rearend. While the rears since 1970 did not offer better rhan 3.42 there is reason to beleive that.the ring and pinions could be used from the earlier rears!!! I have a 1973 and I want 3.64 or 3.91 for it. Several people have expressed interest in looking into the cost of building this ring and pinion new, but even so we need more proof of what will fit what and of courseone to measure from Any nput wll be greatly appreciated. <BR>ed Leaman ROA 9258, BCA 5201, GSCA and abig fan of <A HREF="http://www.v8buick.com" TARGET=_blank>www.v8buick.com</A> <BR>Your use of Yahoo! Groups is subject to the Yahoo! Terms of Service. <P><BR>Your use of Yahoo! Groups is subject to the Yahoo! Terms of Service.<p>[ 03-10-2002: Message edited by: Ed Leaman ] Link to comment Share on other sites More sharing options...
NTX5467 Posted March 14, 2002 Share Posted March 14, 2002 Y'all have found some good information, but here's a "qualifier" on any rear axle gear change -- you have to have a matching "case" (what the ring gear bolts to) for a given gear ratio range (i.e., 2.73 - 3.42).<P>The difference in the cases is that there must be a particular build thickness of the mounting flange for the ring gear on the case and the gear itself. Hence, different thickness mounting areas for the ring gear itself (which further relate to the physical diameter of the pinion gear). The aftermarket vendors get around that by supplying a spacer to maintain the same build thickness with their lower gear ratios.<P>By the early 1970s, exhaust emissions were measured in "grams/mile" instead of the previous "parts/million" orientation (which is independent of how far the vehicle travels per engine revolution). This is the main reason that deeper gear ratios vanished in that time frame--plus the reality that not that many people bothered to order the deeper gear ratios.<P>So, to determine whether or not the deeper gears will actually fit the axle, check for corresponding case part numbers for the more normal gears (i.e., 3.42, 3.08) between the early and later models. If they are the same and use the same bearings and axle shafts, then a corresponding case for the earlier model deeper gear ratio will probably cross breed. Sometimes, you have to approach these deals "from the back door" to see if they'll work.<P>Just some additional items I suspected I'd better mention.<P>Enjoy!<BR>NTX5467 Link to comment Share on other sites More sharing options...
Guest Posted March 21, 2002 Share Posted March 21, 2002 Well I'm glad to be back, was on the road for the last 10 days through the midwest. If I understand you right you are saying that there should be shared diff carriers as well as ring and pinions if this crossover is going to work. I sure hope that we get a couple of measurements to work with from some of the earlier rear ends like the 64 through 70 Rivs' with the deeper ratios<BR>Ed Link to comment Share on other sites More sharing options...
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now