dnthaslethehoff

im redoing my rearend and am torn between going with a 3.55 or 3.80 ring and pinion setup (unless someone has a better idea! lol). my 302 is stock with a few mild mods right now, and the stock 3 speed tranny. what should i do?

2+2GT

How and where do you drive? Highway, or city streets? Daily drive or cruise night?

67mustang302

And what are the plans for the car?

dnthaslethehoff

ill be driving it city, little hwy, car shows...eventually i wanna do some mods to the motor (nice cam ect.) as of now it has aftermarket carb, exhaust, ignition, and a few other things.

2+2GT

I'm leaning toward 3.80 after that description.

67mustang302

How much in terms of mods? Mild mods then a 3.80 would be fine, but if you plan on building a bigger stroker or a blower setup, you'd be better off with 3.55's or maybe even 3.25's.

dnthaslethehoff

thats what i was thinking...its a mild car but with that upgrade from the stock gears should make a big difference for me without spending a fortune. how much of a difference will i really notice going from the stock 2.70-3.00 (not sure which) to a 3.80?

dnthaslethehoff

i want a better launch i guess, just some more bottom end and when i pass make it alittle easier.....

67mustang302

Going from the stock 2.79 to a 3.80 will be a HUGE difference.

I went from a 3.00 to a 3.55 and it was quite noticeable.

Jonk67

Here's a gear calculator, plug in your tire height, tranny should be 1:1 in 3rd and different gear ratios and it'll tell you what RPM you'll be at at different speeds. I made a spreadsheet so I could compare across the lines and put in 50 -110mph to see what it'd do to my RPM's.

I mainly looked at 70-80mph since that's my interstate cruise speeds to see what RPM's I'd push for sustained hwy. driving (>15min. worth).
http://www.ringpinion.com/Calc_RPM.aspx
Jon