Ford 9" Gear Ratio Help

Currently restoring a 1962 Mercury Monterey convertible S55. This car has a mildly hopped up 390 and a 3 speed Merc-O-Matic. She came stock with 3.00:1 axle ratio. I will soon rebuild the rear end, (bearings, seals etc.) and would like advise on if I should change the gear set at that time, and to what ratio. And what would be the benefit of changing? This will be an around town cruiser. Not a super show car, and not a daily driver, just a fun car, semi hotrodded....
Hope to get some info.
Thanx for looking....

 

I'd think that the 3.0 ratio would be pretty good for what you plan to do and with that engine/trans combo. Those engines can loaf along all day long at 70/80 with that ration and never whimper but still have a bit of poke away from the stoplight. Dropping down to something that gives you a lot more grunt off the the line will end up eating more gas in most cases along with causing the engine to rev higher on the highway.

 

Yep, 3.00 is a good match for a manual, though anything down to 3.55 will really pep it up. Don't venture to 3.73 unless you plan to give up highway driving.

 

unless you install an AOD! then it's just right. your 3.00 gears sound right though with your 3 spd.

 

X2---good combo.

 

For what you're doing, don't give up what you've got.

 

^^^^^

Ditto. That 3:00 gear set is about perfect for the kind of car it is and for the usage you outlined. Yeah, some 3:50's would feel a little stronger off the line, but not so much so to make the compromise of gas milage and freeway cruising loss that you would experience.

Don

 

x3.

 

Yep ran 3.00's with my FE's and they liked it. they make plenty of torque anyway so for street driving and no strip action 3.00 are perfect.

 

I agree, I ran a mildly hopped up 390 in my '65 (ford) and the 3.0:1 gear and got around town just fine. It cruised well on the interstate too.

The engineers did a good job of picking a gear for those old boats.

 

You want one more?.......
You'll be fine.

 

Before any final decision on rear end ratios I always consider what I am using for tires, I beleive that Mercury used 7.50X14 tires which work great with your 3:00 ratio that would change if you go to a larger taller tire. Just another part of the equation that need consideration.

 

No No No you need 411 gears I'll trade you---------wish I had taller gears

 

Since the 390 isn't going to be a high winder usually, the 3.00 gear set is a great choice. You could change it to something up around 3.50, but considering the cost it's not really worth the expense for a small gain in low end acceleration.

 

Leave them alone
x 4 ^ ^ ^ ^

 

I compromised with 3.25:1. Best of both worlds. Not too high and not too low.

 

Okay, okay. I got it and am stayin with what I got.Thanx a bunch...