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What is a good rear gear ratio?
I am currently rebuilding a 351c, some components are aluminum heads and intake and a comp cam with 230 int/exh at 050. I am also swapping the cruise-o-matic for a 4 spd toploader. I know I need to redo my rear end gears, but I am really unsure on what a good ratio would be? I plan on driving it mainly intown and would like some getup off the line. Any suggestions would be appreciated.

'72 Mach 1
Good all around gear without a OD is a 3.50 set!
yeah 3:50-3:73 are popular for the street.

[Image: 25rnz1y.jpg]

I added 3.50 gears in my 72 w/a 351c and happy with it.
I have 3.90 in mine. They were in my uncles and he went with 3.50's and likes them but I liked the 3.90 better.
I agree with Tnfastback, 3.91:1 if you can find them these days. Most makers have gone to 3.89:1, close enough. It depends on what you want the car to do and what you are willing to trade to make it do it. In 78 I was driving an R code Mach to work with a 4.86:1 gear in it. A real hoot but very radical.

Good Luck,
Putting 3:50-1 in the mach right now...

"Life is what you make it......"
Check out roushyatesparts.com, they have several used gearsets in kinda odd ratios but you cannot beat the price. I'm looking at a 3.22:1 set. Their sets are all deburred and polished.

Jeff T.

Low buck, touring style, '73 Convertible "rolling restoration", 351c, 2v heads with a shave and a haircut, Performer intake, Holley 650(ish), roller rockers, screw in studs, guideplates, stainless valves, Duraspark / Motorsports MSD, T-5 conversion. 1-1/8" front, 3/4" rear swaybars KYB shocks and some home brewed subframe connectors. Future plans; JGC steering box, Cobra brakes and... paint, interior, etc.

When I die I want to die like grandpa, peacefully in my sleep... not screaming, like his passenger.

[Image: 1_12_09_14_10_15_11.png]
I have 3.50 non posi. Does it or will it make a big difference by adding posi traction instead? when you first take off does posi make a big difference (pick up wise) as far as racing someone in town?

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