I am rebuilding a 12 Bolt and will be going with lower gears. Has anyone out there run both ratios and which one did they like better in thier Buick. I will be running them in a 70 GS455 TB400 with 2000 stall and am also rebuilding a motor so I can change my cam to suite things the best. Any input would be appreciated from the community. Brad White Austin Texas 70 GS455 o No:
Brad In the past you had mentioned running NOS. I do not know if this is still the case. I know Kerry runs 342's and prefers a mid level gear I.E. 342 or 355. From all my reading buicks like 355 gears. I am going to be running 342 once a buddy comes over to help me set up the gears and install the posi. Thats after it comes back from the paint shop.
I picked up .2 by switching from 3.42 to 3.73. It may also have been because the posi was on it's way out with the 3.42 rear.
I'm running 3.73's with a 28" tire. The rpm's are starting to get on my nerves on the highway, 3100 at 70 mph. But for the strip, it's great. I go through the traps at about 5300 rpm on a 26" slick. If your car is mostly street driven, I'd stick with the 3.55's. I'm going to be putting in a 2.73 rear in my car after Norwalk.
Humm so far 2 for for 3.55 and one for 3.73. Greg did the 3.73 bug you on the street or was it a toss up from 3.42 to 3.73????? Does anyone else want to way in on this?? Brad
i'm partial to my 3.42... of course my only other experience is with a 2.56 one wheeled wonder... it's great for street and strip.. granted 3.55 isn't all that much of a difference from 3.42 so i guess my vote goes to 3.55.. it all depends on how much you wanna drive it on the street.. your RPMs will certainly get higher as a result of putting in the 3.73... i was thinking of going 3.73 when i switched.. then thought, well this car is my fun street car.. if and when i decide to build a monster of a race car.. thats when i'll go beyond the 3.42.. my dad still says i should've went to a 3.73... i'm more than happy with the 3.42 and i definately notice the rpm's are significantly higher at 55-60 just from that.. she's yet to go on the expressway.. and i've owned it for 5 years almost lol... we'll see, i plan to trailer it to salem if my friend is gonna let me use his trailer.. if not it'll be driven.. ya i know you guys hate it when people trailer their cars.. i just want the trailer in case i break something.. i'd hate to be stranded ya know? just a safety precaution
Well, i'm use to the overdrive in my GN so both gear ratio's are kind of annoying with the th400. I changed the whole rear because the original cone posi was going in the car so I threw a whole new rear in (yes, the original is tucked away in the garage). There is a small difference RPMwise driving down the road, but it dosen't bother me. I don't put many miles on the car per year so I don't mind the 3.73's at all. For me, if I had to put new gears in my car I would put another set of 3.73's in there.
Brad- I am in the process of putting a 3.73 set in my 72 A-Body, up from 3.08. I see they are now saying gas in the $2.00+ range a gallon this summer GULP. Hope I didn't make a mistake. One thing that does help is I'm running a 700R4 with a lock up torque converter. Mike D.
I have driven 2.93, 3.08, and 3.90 and lower. That said, I would prefer something right around the middle or lower numerically, such as 3.30's or 3.42's. Trust me, the high revs and "stuck in the mud" feeling when you let off the gas on the highway with low (high numerical) gears wears you down. At least it does with me anyway. I'd rather go middle of the road and have liveable rpm's on the highway and still be able to have some off the line grunt. I think 3.30's to 3.55's are a good target. But that's just me.
Thanks everyone! Check out the prices on www.emporium.markwilliams.com . They have Eton Posi for $310 and gears and posi for $430. Looks like I will go with 3.42 after all due to the price savings. Thanks Brad
I've swapped more rear ends in and out of my 71 GS than I care to remember playing the lets try a different gear ratio game. I tried 3.73's to 2.73's and everything in between. With a stock T400, my favorite gear ratio was 3.23's. Then I put a 3.0 low gear T400 in with a 2.93 geared rear end. This is now my best set up yet. The bottom actually improved over the 3.23s, and the cruising around RPM's are much better with the 2.93's. Freeway cruising is no problem now, where it used to start to get on my nerves after awhile. Anyway, thats my take on this issue.
I have 3.73's with a 2004R lock-up. if I didn't have four gears the high revs would drive me crazy. :rant:
I would recommend 3.42 gears. The Buick engine produces a tremendous amount of torque, and by using a very low geared rearend you could end up wasting that torque. The chevy engines for example needed that very low geared rearend since they didn't produce as much torque as our engines do. Plus you'll be much happier on the freeways :TU:
Rear Gears Todd, is right!!! I went from 3:08 to 3:42 and is perfect to match the super torque of a 455 in the final match RPMs to MPH. Go with 3:42s, :3gears: AL.
Gear Choice I was talking to another club member last weekend about gear ratios and he said he didn't care for the 3:55 and the liked the 3:42 much more. Good luck on the installation, AL.
