Technical 39 Box with Zephyr gears What rear end ratio?

I am running a 39 Trans in my Roadster with Zephyr gear set and 4:11 Rear. It is perfect around town and not bad on the highway, but a bit more cruising speed would not be a bad thing. The reason I am asking is that I need to pull the rear soon since it sounds like a bearing is going bad. So while it is out I thought about 3:78's . I have been told that 3:54's with the Zephyr's is like starting in second gear. Has anyone had experience with 3:78's and the Zephyr's? Again the 4:11's are perfect most of the time.

 

For all-around use, 3:70s with a slightly taller tire than stock will be a good combo in a light car, especially if your engine is warmed up.

 

Running 700 's right now in the rear. May go to 7:50's

 

I have a roadster project underway. Am running 25 tooth Zephyrs with 3:70 gears and 7:00X16 tires. I figure it's the equivalent of a 3:54 with stock tires (6:00X16). 4 1/8 stroker motor so should have plenty of torque for the taller setup.

 

I would think that 3.7-3.8 gear with a 30" tire would be a good combo. I can't say for all 7.50s but my last set of 7.50x16 were rated @ 32" dia (actually mounted in 5" rims that came out closer to 31") I probably would not want to run a 32" tire with your drivetrain ending in a 3.7 gear. I don't think even with a light car that you would have much if a hole shot.

Just my thoughts on the subject.

 

Seriously, have you thought about putting a quickchange in it, and changing the spur gears for long trips? I know its $$$, but hey, it looks and sounds cool too, and you get to keep the scoot around town.

 

Would have to change rear cross member and at this point I do not want to take the 32 all apart again. It is a finished car.

 

What is this "finished" you speak of??

 

Good Point

 

Damned auto correct strikes again, he meant Finish not finished. I wasn't aware that they made cars in Finland.

Well google strikes again here is one.

A Korvensuu



You maybe could get the quickie in there without blowing the car all apart. But it would involve a lot of laying on your back and welding overhead.

 

That is not a problem since welding was my trade for 40 years. But getting off the ground may be.

 

Think about the Zephyr...they utilized that gear set with 4.44 rear, giving them plenty of dig and a nice close ratio box, and got their top end back with overdrive. An ideal setup for your rig would be to go down on the gears to 4.11 or 4.44, then, to avoid dicing crossmembers and rebuilding whole damn car, put in a Mitchell torque tube OD... you could have your cake and eat it too, for less than the cost of your house!

 

I do get that getting off the ground bit. I am actually thinking about putting a lift in my next garage.

A couple of years ago I did some chassis mods and repair on an old Lincoln and keep one of those miny stepladder/stools close to help me up off the floor.

 

Never heard of a Mitchell torque tube OD. What and where? I have 4:11's now and love the car around town.

 

Refresh memory, what is your engine?

 

its a good idea, if the look doesn't bug you too much...I'll try google, see if they have a website...

 

http://www.mitchelloverdrivemfg.com/our-products/

 

It is a 1933- 21 stud with a Merc 4" stroke crank (240 cu.in.), + .20 over bore, Isky 400 lift cam (adj. Lifters),
two 97's.

 

Mitchell is expensive and ugly (though hidden), but OD really suits your combination. A gppd Lincoln overdrive trans might cost a thou and would require hacking your frame, a Columbia would cost a fortune ready to go...the Mitchell seems pretty well proven now and fits into ford without disturbing crossmembers.

 

I should have asked trans ratios but I think I just read in another thread that 1st is 2.54...Going from 4.11 to 3.54 is 14% reduction, engine rpm would be .86 of what it is now at 60 mph....Idling in first gear would be around 1-2 mph faster..I think you would be fine, 4" crank and not too heavy car...

 

Bruce didn't the Zephyr use the Colombia 2 speed?

 

Zephyrs used some columbias, but in 1940 they got a BW overdrive on the back of the transmission...this trans (the actual source of Zephyr gears) will bolt to a flathead and to a shortened torque tube and would be a neat piece in a Ford, but would require a bunch of crossmember hacking.

 

There is some one doing the conversion with a Volvo OD, actually made by Laycock de normaville. I believe the firm does the conversion, you just send them the TT and OD. Pay them an exchange price and get it back "plug and play" ready to install.

It should be fairly easy to find an old Volvo 240/260/740/760 and buy the trans for cheap, and if you breaks it (they can't hold up to being 1. Or reverse OD. But you can run them as a split on you 2 and 3.

Need setup, and the 240 should be dirt cheap, compared to the older models, same OD, but it's more rare.

 

Well I certainly wouldn't be beyond hacking a cross member or two.

Good to know thanks.

 

http://www.fordbarn.com/forum/showthread.php?t=12110

Look at this.

 

This is the '48 Lincoln trans with overdrive for a visual comparison (the same setup that Doane Spencer used). And this is the******* that people take the gears out of to put in the Ford box.

DoaneSpencerchassis

It will bolt to the flathead, but will require torque tube modification, and crossmember. Bob

 

As said I am already running the Lincoln gears in the trans, and I am very happy with the car with the 4:11's. Just wondering if it is worth going to 3:78's?

 

I just happen to have two of these...

 

If it were me, I would just leave the 4.11s in it, at least until I found some 4.44s out of a V8-60... But then, I run 4.5s in my daily, so...
Apparently, that means I'm not a proper "traditional" hot rodder, but some kind of crazed sociopath street racer, hell bent on the rending of our social fabric, and the destruction of all that respectable hot rodders hold dear...

 

Hot Rods to Hell! That is what I always say