If you have any kind of performance cam, the 3.00:1 ratio will be a disaster. I tried it. I know. I then tried 3.89, 3.70 and 3.50.  The 3.89 was too much. The 3.70 was the absolute best for spirited performance driving, and got good mileage on the highway. I now have 3.50.  More like a normal car, not a performance gear. But still pretty steep on takeoff. I notice the Kias and other normal cars pulling away as I leave stoplights. Since I have a boatload of torque with my 427, I am considering trying a 3.25 setup, but would NEVER consider a 3.0 unless I had a near-stock camshaft. With the 3.0 and 400 hp 351, I could not use fifth gear under 70 mph

Overall, I estimate I have wasted $5,000 trying to get proper rear ratio and a gear set that doesn't make noise.  Still haven’t solved that one.  Every single set of 9” gears have made noise. It seems the more “big name” of a company they came from, the more noise they made.

I would assess the rear gears AFTER you get the trans in the car and drive it. 

MS wrote:

TKOPerformance wrote:

I would assess the rear gears AFTER you get the trans in the car and drive it. 

BINGO!!!

The Trans has been in the car for 1 year, Its out now for some service and inspecting the clutch. My exprience driving the car with 3.5 is that it feels like a tractor :-) on first gear. But 3.25 should be the way to go.

TKOPerformance wrote:

So consider this:  with a 3.27 first and a 3.5 final drive your overall first gear ratio is 11.45, which I would consider to be too tall for a typical V8 naturally aspirated car.  A swap to a 3.25 final drive nets you a 10.63, which is closer to the theoretical ideal of 10:1.  I agree with MS that a 3.00 is going to be too low, because that puts you on the other side at 9.81.

3.25 seems the best way to go, Thanks.

It must be an Right coast/Left coast thing.

I grew up referring to first gear as "low" and third gear as "high".  So when talking of final drive gears the closer the ratio, the "higher" the gears were considered to be.....3.00:1 is "high" or tall, long legged.  4.86:1 us "low" or short.
For a lot of guys it's just the other way around.   Just sayin'.

Bullet Bob wrote:

It must be an Right coast/Left coast thing.

I grew up referring to first gear as "low" and third gear as "high". So when talking of final drive gears the closer the ratio, the "higher" the gears were considered to be.....3.00:1 is "high" or tall, long legged. 4.86:1 us "low" or short.
For a lot of guys it's just the other way around. Just sayin'.

People get caught up in the difference between "numerically" low or high and low or high, and tend to use the terms interchangeably when they mean polar opposites.  I agree its confusing. 

TKOPerformance wrote:

DC wrote:

My favorite gearset for my Mustangs is the good old 3.73. BUT I don"t use the Mustangs for long cruises. The motors I installed in the have enough torque to be really fun with the 3.73. When I race I go to the 4.10 or 4.30! Tranny's are 5 speeds with the .68 5th. Neither Mustang right now has anything that even slightly resembles a muffler so long trips are not on the agenda. The 3.73 gives good launch and off the corner grunt is smile making.

What's first gear in the trans?  I run a 3.73 in my IROC, but it has a 2.66 first in the T56, so its right about perfect.  If you have a 2.99 first then a 3.73 is fine, especially for racing if the engine has a high powerband. 
 

The race motors see 8300 quite often, they are Motorsports block based and all forged and well balanced internals.

Mach173 wrote:

Great info,Thanks  the cam is a howard roller. Pretty standard I would say.
Basic RPM Range: 1600-5600
Manufacturers Description: Mild idle, great all around street, good low end torque & horsepower.
Intake Duration @ .050": 217
Exhaust Duration @ .050": 225
Advertised Intake Duration (@ .006"): 270
Advertised Exhaust Duration (@ .006"): 278
Intake Valve Lift with OE Rocker Ratio (1.73): .571"
Exhaust Valve Lift with OE Rocker Ratio (1.73): .577”

Maybe I just leave the 3.50 in hmm
 

What is the LSA?!
(To me) that tells A LOT about camshafts and how they perform...

LSA people!!!  & Duration @ .050 tells almost everything about a cam.
Lift figgers has zero effect on how a cam acts at low speed/around town
6sal6