The Ford Barn

42merc/ma · 01-24-2012, 09:32 AM

Thinking of relocating to Florida. I own a 42 Merc with 3.78 rear, thinking of going to 3.25. What kind of a job is this and will I be able to get the right gear for the speedometer? Thanks.

19Fordy · 01-24-2012, 09:36 AM

Will you be changing out the entire rear end for another, like an 8 inch?

Charlie Stephens · 01-24-2012, 11:28 AM

It might use the same speedometer gear as '31 Model A. If so,try Berts (303) 293-3673 or Bratton's 301-253-1929.

Charlie Stephens

deuce lover · 01-24-2012, 12:49 PM

You will need the 17 tooth speedo gear for the turtle.

ford38v8 · 01-24-2012, 01:29 PM

With a 3.25, you might be able to cross the intersection before the light turns yellow.

42merc/ma · 01-24-2012, 02:27 PM

Sponsored Links (Register now to hide all advertisements)

19Fordy, I was thinking about getting the Getz gear set from Speedway. Maybe 3.54 would be better, I am not sure. Looking for better cruising speed.

rotorwrench · 01-24-2012, 02:39 PM

I didn't know anything with a number lower than 3.54:1 was made in that time frame. 1942 probably had the two part rear drive with the coupling but the earlier Mercury cars had a one piece drive shaft pinion combo. It made those early ones a bear to work on.

19Fordy · 01-24-2012, 02:41 PM

Quote:

Originally Posted by 42merc/ma

19Fordy, I was thinking about getting the Getz gear set from Speedway. Maybe 3.54 would be better, I am not sure. Looking for better cruising speed.

Here is an earlier thread about this subject. Living in FL I can honestly say that a 3:54 ratio will be just fine. Very few hills. If you do decide to make the change keep us posted and take plenty of pictures. Where in FL are you moving?
https://www.fordbarn.com/forum/showth...=getz+gear+set
and
http://www.jalopyjournal.com/forum/s...3472&showall=1

Type the words "how to install getz gears in a banjo rear end" into your Google box.. Lots of info pops up from guys who know what they are doing that you will enjoy reading.

42merc/ma · 01-24-2012, 02:46 PM

West Palm Beach area.

19Fordy · 01-24-2012, 03:09 PM

Quote:

Originally Posted by 42merc/ma

West Palm Beach area.

A good friend of mine with a 40 Ford lives in West Palm Beach. You will enjoy the car activities such as Abacoa monthly car show, etc.
Just wondered as I am 1 hour south of WPB.

42merc · 01-24-2012, 05:55 PM

Have you actually checked the ratio on your '42 Merc? Most all '42 Mercs were equiped with 3:54 ring & pinion gears with a coupling for the driveshaft.

the42nut · 03-20-2016, 02:09 PM

Hey 42merc/ma You never mentioned what body style Merc you have? I keep track of most of them out there, and I don't think I have you listed. Did you move to Fla? I could put you in touch with the 42 Merc owners down there. Would like to talk to you or email. [email protected] Even if you don't have the car any more, I still would like to talk to you about 42 Mercs

Ol' Ron · 03-20-2016, 02:31 PM

Why not a Mitchael??

Mac VP · 03-20-2016, 05:44 PM

The best ratio would be the 3.54. If you have the 28 tooth cluster gear in your trans you'd have to slip your clutch too much every time you started out from a stop. Even the 3.54:1 ring and pinion benefits from a 29 tooth cluster gear. We sell many 3.54 gearsets compared to the 3.25 set.

my4dv8 · 03-20-2016, 05:58 PM

Yes, 3.54 with 750 x16 rears is plenty adequate. This will put you at around 2500 rpm at 60mph.

edhd58 · 03-22-2016, 08:09 AM

Yes, 3.54 with 750 x16 rears is plenty adequate. This will put you at around 2500 rpm at 60mph.

Will this be true of a 42 Ford 6 cylinder, 3 on the tree, 650 x 16s with 3.54 gears?

Mart · 03-22-2016, 08:15 AM

No you will be revving a bit higher by having 6.50s instead of 7.50s. I haven't checked the original figure, but all else equal, the tyres are different.

Mart.

JSeery · 03-22-2016, 09:23 AM

Quote:

Originally Posted by edhd58

Yes, 3.54 with 750 x16 rears is plenty adequate. This will put you at around 2500 rpm at 60mph.

Will this be true of a 42 Ford 6 cylinder, 3 on the tree, 650 x 16s with 3.54 gears?

The engine doesn't matter as far a RPM numbers go. It is determined (in high gear) by the rear axle ratio and tire size, regardless of engine type. As Mart stated the tire size will make a difference. Off the top of my head I think I remember it being about 200 RPM difference, but I could be wrong!

JSeery · 03-22-2016, 09:30 AM

Here is an RPM chart from Summit for 60 MPH. You can find the tire diameters by going to one of the online tire suppliers, many of them list the diameters in their specification tables. The formula is MPH X Axle Ratio X 336 all divided by the tire diameter.

edhd58 · 03-22-2016, 10:03 AM

I was hoping someone reading this post would know the trans gear ratios to know if mine was close or the same as 42 Merc/Ma. Merc what trans do you have in yours so I can look up the final drive ratios. Thanks

01-24-2012, 09:32 AM	#1
42merc/ma Junior Member Join Date: May 2010 Location: middleboro, ma Posts: 20	3.25 rear Thinking of relocating to Florida. I own a 42 Merc with 3.78 rear, thinking of going to 3.25. What kind of a job is this and will I be able to get the right gear for the speedometer? Thanks.

01-24-2012, 09:36 AM	#2
19Fordy Senior Member Join Date: May 2010 Location: Coral Springs FL Posts: 11,068	Re: 3.25 rear Will you be changing out the entire rear end for another, like an 8 inch?

01-24-2012, 11:28 AM	#3
Charlie Stephens Senior Member Join Date: May 2010 Location: Southern California Posts: 7,075	Re: 3.25 rear It might use the same speedometer gear as '31 Model A. If so,try Berts (303) 293-3673 or Bratton's 301-253-1929. Charlie Stephens Last edited by Charlie Stephens; 03-22-2016 at 10:38 AM.

01-24-2012, 12:49 PM	#4
deuce lover Senior Member Join Date: May 2010 Location: Southern France Posts: 5,341	Re: 3.25 rear You will need the 17 tooth speedo gear for the turtle.

01-24-2012, 01:29 PM	#5
ford38v8 Senior Member Join Date: Jul 2011 Location: SF Bay Area Posts: 6,689	Re: 3.25 rear With a 3.25, you might be able to cross the intersection before the light turns yellow. __________________ Alan

01-24-2012, 02:27 PM	#6
42merc/ma Junior Member Join Date: May 2010 Location: middleboro, ma Posts: 20	Re: 3.25 rear Sponsored Links (Register now to hide all advertisements) 19Fordy, I was thinking about getting the Getz gear set from Speedway. Maybe 3.54 would be better, I am not sure. Looking for better cruising speed.

01-24-2012, 02:39 PM	#7
rotorwrench Senior Member Join Date: Jun 2010 Location: San Antonio, Texas Posts: 16,574	Re: 3.25 rear I didn't know anything with a number lower than 3.54:1 was made in that time frame. 1942 probably had the two part rear drive with the coupling but the earlier Mercury cars had a one piece drive shaft pinion combo. It made those early ones a bear to work on.

01-24-2012, 02:46 PM	#9
42merc/ma Junior Member Join Date: May 2010 Location: middleboro, ma Posts: 20	Re: 3.25 rear West Palm Beach area.

01-24-2012, 05:55 PM	#11
42merc Senior Member Join Date: Feb 2011 Location: Buchanan, MI Posts: 677	Re: 3.25 rear Have you actually checked the ratio on your '42 Merc? Most all '42 Mercs were equiped with 3:54 ring & pinion gears with a coupling for the driveshaft.

03-20-2016, 02:09 PM	#12
the42nut Junior Member Join Date: Nov 2015 Location: Miwaukee, Wis Posts: 5	Re: 3.25 rear Hey 42merc/ma You never mentioned what body style Merc you have? I keep track of most of them out there, and I don't think I have you listed. Did you move to Fla? I could put you in touch with the 42 Merc owners down there. Would like to talk to you or email. [email protected] Even if you don't have the car any more, I still would like to talk to you about 42 Mercs

03-20-2016, 02:31 PM	#13
Ol' Ron Senior Member Join Date: May 2010 Location: Chester Vt Posts: 8,926	Re: 3.25 rear Why not a Mitchael??

03-20-2016, 05:44 PM	#14
Mac VP Senior Member Join Date: May 2010 Location: Cincinnati, OH Posts: 1,374	Re: 3.25 rear The best ratio would be the 3.54. If you have the 28 tooth cluster gear in your trans you'd have to slip your clutch too much every time you started out from a stop. Even the 3.54:1 ring and pinion benefits from a 29 tooth cluster gear. We sell many 3.54 gearsets compared to the 3.25 set. __________________ VANPELT SALES LLC Cincinnati, Ohio Office: 513-724-9486 www.vanpeltsales.com www.classictransmission.com

03-20-2016, 05:58 PM	#15
my4dv8 Senior Member Join Date: Aug 2010 Location: New Zealand Posts: 1,115	Re: 3.25 rear Yes, 3.54 with 750 x16 rears is plenty adequate. This will put you at around 2500 rpm at 60mph.

03-22-2016, 08:09 AM	#16
edhd58 Senior Member Join Date: Jul 2014 Location: Guston,ky Posts: 653	Re: 3.25 rear Yes, 3.54 with 750 x16 rears is plenty adequate. This will put you at around 2500 rpm at 60mph. Will this be true of a 42 Ford 6 cylinder, 3 on the tree, 650 x 16s with 3.54 gears?

03-22-2016, 08:15 AM	#17
Mart Senior Member Join Date: May 2010 Location: Solihull, England. Posts: 8,806	Re: 3.25 rear No you will be revving a bit higher by having 6.50s instead of 7.50s. I haven't checked the original figure, but all else equal, the tyres are different. Mart.

03-22-2016, 10:03 AM	#20
edhd58 Senior Member Join Date: Jul 2014 Location: Guston,ky Posts: 653	Re: 3.25 rear I was hoping someone reading this post would know the trans gear ratios to know if mine was close or the same as 42 Merc/Ma. Merc what trans do you have in yours so I can look up the final drive ratios. Thanks