78Cutlass4Speed

I'm looking to change the gears in my rear end and want to know what company makes the best set. I know Richmond has been around for a long time but I've heard from several people that their gears are... "noisy". I see listings for Precision, Motive, Yukon, Excel, and also private labels like Summit and Jegs. The rear in my 1979 Hurst/Olds is an 8.5" 3.73 posi rear out of a 1985 442. The 3.73's are great for acceleration but suck on the highway. I'm turning about 3300 rpm on the highway at 65mph. 3.73's are too much gear! I was thinking about an overdrive transmission but can't justify the cost. I think a set of 3.23's will be ideal. I'll have better cruising and lower rpms. Plus, I'll probably get better than 8-10 mpg. So... who makes the best gear set?

70sgeek

"best" is a relative term - as in relative to anyone with an opinion...


Tire size also matters - larger tires will help keep the revs down.


you may want to look at 3.08 gears if highway cruising is your concern - as example, my prior '72 skylark turned about 3500 at about 65mph with 3.23 Posi gears, my current '72 cutlass turns 3000 at 70mph with a 3.08 Yukon Posi gear set and the same size 245-60-15 tires that the skylark had. Both cars with TH350 trans as well.


the Yukons are quiet and in my opinion a good compromise for performance cruising.

Qwik71442

Installed many a Yukon gear sets and everyone had a real nice pattern and very quiet. Cost a little more but you get what you pay for....

monzaz

You really should think about the overdrive...I am personally telling you that you will drive the car a lot more with the overdrive trans.

I have a 454 SS 1971 Monte Carlo and a 700r4...I drive it freeway drag race it do burn outs...JUST a great deal for the guy/Gal that wants everything.

Just be sure you get someone that knows what they are doing. The 200 and 700 overdrive trannies pretty much have all the kinks worked out and tons of aftermarket performance parts have taken care of any failure issues.
I have had mine for 15 years no issues. still beating the pulp out of it...

Jim
J D Race

PS 3.23 will be fine but as statd depending on the tire size ....that will determine the loss of low end and gain of top end. ALSO the motor torque will help determine how much you can remove from gearing...big block cars will not need as much low gear even 3.08 will work nicely....Problem here is you are use to the 3.73 and that will be hard to give up. Jim

78Cutlass4Speed

Not sure which route I'll take- gears or OD transmission. Tough choice. Both have pros and cons. I have a built Turbo 350 in the car now and the stock 205/70R14 tires on the original Hurst rims. Changing gears would be the easier (and cheaper!) route. I'll have to change the crossmember and get a kit to convert my 3 speed Hurst shifter to work with the 4 speed pattern. If I go with a 700R4, I'll also need an adapter plate to mate it to my Olds 455... Seeing the dollar signs add up. A 200R4 would be an easier installation. I have the money right now to do either swap so that's not a factor.

monzaz

Just remember...Do what works for you.... I am not driving your car or own your car. So if you want or can deal with your choice and it works for you...Go ahead and do it. I am just going an opinion what worked for me. I would NEVER hold a grudge etc for not going my route... As you stated both can work. Jim

78Cutlass4Speed

I've also toyed with the idea of dropping in an Olds 350 and bringing it back to stock. I still have the 7.5" 2.73 rear end and all of the original parts (except the engine) to do so. I also have a 200R4 from a 1987 442 (KZF code) and D5 converter sitting in my basement. I could keep the 3.73 rear and swap in a mild Olds 350 and 200R4. Lots of possibilities. I just haven't made up my mind yet.