Another 2.94 vs 3.55 thread

[Koronetti70]

Hello.

I was just wondering what's everyone best quarter mile time and speed with 2.94 gears. On the other hand, what's everyone's best mpg or longest road trip with 3.55 gears.

We're having a "debate" with my father about if it's going to be a total slug with 2.94 gears or a pain in the *** on road trips with 3.55 (those are what we have on the shelf). It's a stock stroke iron head 440 with better pistons, cam, porting etc.

Wouldn't mind the higher gears as it's going to see the strip probably once a year at most but it's definitely going to be daily driven and taken for road trips. And the gas is close to 8$ a gallon over here. But wouldn't want it to not accelerate.

A five speed would probably be the correct answer.

 

[ruffcut]

At 8 bucks a gallon, stick with the 2.94 gear

 

[MWbirdLOVER70]

I like my 3:91 but built my motor heavy. 3:23nice gear and 3:55 I like but but for me and my driveline 3:91 perfect but with 14.0 tires I push 3k rpm at 52-55 mph so given that I I’m the last one in the group to go over an hour to shows when I go along

 

[RemCharger]

It's a pretty uncomplicated decision. Good gears- quicker/ higher rpm. Shitty gears- less quick/ lower rpm.
I'd say for you go for the 2.94s as that little ( .5 mpg?) Seems to be most important to you

 

[MWbirdLOVER70]

It's a pretty uncomplicated decision. Good gears- quicker/ higher rpm. Shitty gears- less quick/ lower rpm.
I'd say for you go for the 2.94s as that little ( .5 mpg?) Seems to be most important to you

To me it’s getting mine out of the hole quicker and staying local but I agree with your point RC

 

[#41]

I think perhaps a long road trip in Finland is like a day trip here in the western US. Here, you might expect to drive 75mph (120mph) for an entire day+ and I would prefer the 2.94s for long trips. For shorter trips, I would be happy with the 3.55 as long as I was running a tall (28 inch plus) diameter tire. For general all-around use, I like the 3.23 combined with a tall diameter tire.

 

[BSB67]

I suspect that the et difference will be small, but engine and torque converter details matter. I also suspect the driving around town “feel” will be very noticeably different between the two. People often times confuse that “feel” with the car running quicker.

I’ve been 11.2s @ 121 in mine with 3.23s. In my car I’m guessing I’d loose a tenth going to a 2.94.

 

[Dave6T4]

This is why Chrysler put 3.23's in so many of their Big Block cars. I had 3.55's in a heavy 1967 3-seat Coronet station wagon, which had a 440, 4-speed, and liked them for local car shows and trips. One year, we decided to use this car to visit family in South Georgia, with a side trip to Don Garlits' Museum in Florida, from Southern Ontario. In preparation for this, I swapped to 2.94 gears, and added a Cordoba cruise control system. This setup worked well for 2 days of driving each way on I-75. I found out was a struggle to get my wagon cleanly launched with a manual transmission with the 2.94's, however.

 

[lewtot184]

I think the wild card(s) would be cam and converter.

 

[dadsbee]

Wild card is how fast you can shift gears. My only time to the Luskville Quebec track, in '79 or '80 my Bee, my stock 383 x 4 gear with 2:94's ran 100 mph exactly.

Best part back then, with 2:94's the cops LTD's couldn't keep up... Now they just shoot vs trying to get you next Friday night!

 

[OMTWF-72SE]

I swapped from 2.96 open to a 3.55 suregrip in my 72 recently. its night and day. hard on my tires, but the difference from a stop, merging onto the freeway and passing is fantastic. don't know about mileage, I don't pay any attention to that when I drive her. gauge gets down to 1/4 and I top her off. over and over and over and over.

 

[Demonic]

Why not get a set of 3.23's? It splits the difference between the other two.

 

[Runcharger]

3.23's are what would work the best but they are not what you have. It depends on if the engine is stock or not and how much town driving you will be doing. Either set of gears will work and compromise a bit with both. "Daily driven", "cam and porting", leads me to believe it will be daily driven in the city with maybe 1 or 2 road trips a month. In that case I think I would try the 3.55 and see how happy you'll be with them. I've tried 3.55 several times and have never been content with them myself. They aren't that deep for performance and they buzz the engine on the highway. 3.23 is 10% better IMO. Our gas is about $8/US gallon here too but I would never let that be a determining factory on an old car. No use having an old car if it isn't fun to drive.

 

[PurpleBeeper]

Hello.

I was just wondering what's everyone best quarter mile time and speed with 2.94 gears. On the other hand, what's everyone's best mpg or longest road trip with 3.55 gears.

We're having a "debate" with my father about if it's going to be a total slug with 2.94 gears or a pain in the *** on road trips with 3.55 (those are what we have on the shelf). It's a stock stroke iron head 440 with better pistons, cam, porting etc.

Wouldn't mind the higher gears as it's going to see the strip probably once a year at most but it's definitely going to be daily driven and taken for road trips. And the gas is close to 8$ a gallon over here. But wouldn't want it to not accelerate.

A five speed would probably be the correct answer.

2.94. I'm running 2.76's right now and it accelerates just fine

 

[old guys rule]

I have 323s with a manual for speed overdrive. 71 overdrive which gives a final drive ratio of 2. 29. Think this may be feasible on the highway? ️ Never go over 75.

 

[RemCharger]

I have 323s with a manual for speed overdrive. 71 overdrive which gives a final drive ratio of 2. 29. Think this may be feasible on the highway? ️ Never go over 75.

What's the lowest rpm you want to lug it at?

 

[old guys rule]

What's the lowest rpm you want to lug it at?

With 27 inch tires it works out to 2000 RPM at 70

 

[old guys rule]

With 27 inch tires it works out to 2000 RPM at 70

Short cam, on it 8.2 to 1 compression

 

[old guys rule]

60 over 440

 

[BobH]

I drove 2300miles for Drag Week this year, 3.55 gear, 496 stroker, four speed. 60mph is 2600rpm which seems pretty comfortable. 12 mpg for the week.