so i put in the 3.73 rear....

[Porklops]

um yeahhh I built a mild 355 for my 78 malibu and was playing for awhile with the stock rear, 2.41? 2.29? not sure which but the massive one wheel peels were fun for a bit. Couple nights ago we finally put the 3.73 rear end i had for it.... holy sh*t!! Im going to get in trouble for doing burnouts...car is useless on the highway now but its a in town/ local car show toy so screw it! what a change, it doesnt chirp second, it spins the tires lol.

 

[-83MONTESS-]

Thats how I felt when I went from the 2.19s to 3.73s. Feels like a whole new car but the highway thing gets old quick...

 

[80ELCAMINOFLAKE]

Nice!!!! thats how i felt with my elco went from 2:73 pig leg to 3.73 posi and wow what a difference....its was fun...but that th350 killed me on the freeway!! she was screaming like krazy

Any plans to update your trans? I have a 200r4 that im putting in my malibu to replace that th350, but going with a posi unit and 3.08 gears this time....

Have fun

 

[Porklops]

car sees zero highway use anyway but yeah, it shifts out of first at 10mph! time for that shift kit now...

 

[azmalibuwagon]

Ha, yeah the 3.73 is fun. I replaced my 2.59 with one. It's a lot of fun but even with overdrive it's no fun on the highway (except for getting on, that part is great). MPG went from 17-18 down to 15, too. I think maybe a 3.28 might be about right.

 

[my86442]

Hell you guys think 3.73's are fun, try goin from 2.73 to 4.11's!!! LOL than you'll look at not chirping a single gear but burnin threw each with a pair of 500 + ft scorchers. That was fun, lol but i found out 4.11 on the highway wasnt a bit of fun. 8 mpg sucked royally. i figured 3.55's would do the trick

 

[Hoopty_Mike]

That's how I felt going from 2.41s to 3.73s, Did you get the correct governor and speedo gear yet? Shaving a little weight off the governor with the correct gears helped me a lot.

 

[dogsht]

Wallace Racing calculator:

All examples using a 3.73 gear with a 27.0" tires ie 255/60/15

th350 trans
2500 rpms
53.86 mph If you don't have a working lock up torque converter it will slip and you will turn about another 2 to 300 rpms more at the same speed.

200-4R trans
2500 rpms
80.39 mph Same or slightly improved acceleration but way less heat load to your cooling system less wear on your motor and up to 33% better fuel economy.

As you can see no need for 3.08s with the 200-4R. But it is an ideal gear for an old 3 speed with the car being used as a driver.

Porklops I would just get a posi & make sure your lock up feature is working. There is another thread on that here on gbody now.

 

[Grandprixpaul]

Wow just about where im at. I have 229 limited slip, with a sbc 350.366hp turbo trans with shift kit. Im tired of the onr wheel spin too. How bad is your trans on the highway?. I really want to go with 355 or 373 gears somewhere in that area.but no higher.have a friend with firebird with almost same set up as me and he has 411s it just crazy

 

[dogsht]

GPPaul, Here is how you answer your own questions and learn the pros & cons to a change.
http://www.wallaceracing.com/calcmph.php

If its still a driver that you want to be able to take out of town with the 3 speed you will like the 3.08 or 3.23 better. A big jump from a 2.29 with most of the acceleration of a 3.73 without the crazy spin the snot out of your motor rpms. But play with the calculator and you will see the rpm to gear to mph. The only part you don't see is the "most of the acceleration" jump without the crazy rpm or going the other way 3.73 to 3.08 to 2.29 is the "most of the mileage" without the sloth acceleration. That stuff you have to take to the track to see or calculate mileage to see but it proves out.