My buddy has a 70 SS with a 454/4-Speed. Currently he is running 2:56's (give or take) and is considering going to 3:73's. I noticed a big change when I did that in my other car but it was an auto.

What do you guys think -- is it worth the cost? He isn't running on the track but wants to have fun Stop Light to Stop Light.

Of course its worth it,,,3.55-3.73's would be perfect and make a big difference.

Birddog,

I would tell him to put it in second and run up and down the express way for an hour at 70 MPH and see how he likes it, before switching to 3.73's. It can get old fast.

Unless he has run gears before he might not know what he is getting himself into, even though 3.73 gears aren't that deep. It will be a world of difference from (? 2.56's ?).

bill

Absolutely.Make the change. :cool:

Fine as long as he doesn't mine 60 mph on the freeway, 355's would be a little better alternative as a road carver but if only thinking stoplight to stoplight go for the 373's! Along with gearing like that a good at least Holley 750dp, cam, and headers would really wake that sweet machine up! :D

I went from 273s to 488s,now that was not worth it,but fun as h-ll,373s? great street gear,IMO
67rat

3.73s are o.k. on the highway,now 4.56s-that's a different story.

I went from 2.56's to 3.31's..
3.55-3.73 would be optimal for my combo,but the 3.31's are a reasonable compromise.

YES

It would be nice to know if its a m20 or 21. If its a m20 3.43 would be good, m21 or 3.55 or 3.73...mike :cool:

and hos speedo wil only be 50% offafter the swap- so the speedo will read 90 when he is going 60.
it sure is fun freaking out people who don't know you didn't get the speedo calibrated yet and they wonder why cops drive right by when you are going "90" in a 55 zone..

I recently changed from a 3.31 to 3.73's.[which was the max ring n pinion change with this hemisphere]What a difference!My eng. is a lot happier at a few x-tra revs and now its on top of the converter,and is a lot happier at low speed limits.I run 295-50 TA's and it sits on around 3k rpms at 100kph-about 60mph?.I dont think I'd go lower gears,but the 3.7s are great all round with 15" tyres.

27" tall tires @ 65mph= 3000-3300RPM with a 1:1 final drive. I had 2.73's (and a th350) and yes it was fun taking 1st up to 80@6000 and bang 2nd playing with "Ricers" but am alot happier with the 3.73's (yes, does feel like 2nd all the time).

No! Very bad idea...

Tell him he needs to take that rear end set and sell it for cheap and forget about ever considering the idea.

(Then give him my email address and tell him I'll take the junk off his hands... :D :D )

I really like my M-20 and 3.31's, but I have a First gen. car, but it is lighter.

They were the stock 350SS gear if you didn't check a gear option back then...

pdq67

I agree with pdq. A very good combination, especially with some torque.

Are you sure about the 2.56s? Even with an M-20 it wouldn't be driveable with that kind of gear. Like has been said 3.55s are a real good street gear in a heavy car.

When I converted my Malibu from a 350 to a 402, I ran my stock open 10-bolt with 2.56s for about 3 months before I bought the 12 bolt w/3.31s. I have an M20 and with the 2.56s, it was a pain in the arse to drive, especially in traffic, and did my clutch an injustice. Anyhow, I agree with Mr 4 speed, the 3.73 would be a better performance choice for my setup as well, but as much highway driving as I do, the 3.31 works well for me. If your buddy does more street than highway, then I say go for the 3.73s, but if the shoe is on the other foot, he might regret it.

My buddy doesn't have the Munci -- he is running a Super T-10. Currently is not a posi but he will be putting in a posi unit when he does the gear swap. The motor doesn't run like a bat out of hell (yet) but he is working on it. Mild cam/holly 750 (vacuum secondary's)/headers.

I'm thinking it would be worth it for ... he doesn't plan to drive on the highway just have some fun around town and wake up the motor.

I run a 3.55 gear, and kinda wish it was a 3.73 for my new motor. It is a great gear though. Go for the 3.73's all the way.