What are the best gears for STREETable HP? Big difference?

3.73's for me. My combo has a higher power band than a stock 5.0. Because I can wind it out to 6,000 rpm, the extra gear is nice.

Deeper gears can make a car more streetable, mainly if you have given up some low-end power. Also, good suspension and good street tires can help out a lot.

I got 3.73's and BFG radials for thetrack. My 60' times are about 1.8. The gears are deff.streetable, just need to be careful in 1st gear when it is wet out. If u do mutch freeway driving go w/ the 3.55. my bro has them in his mustang and they are much better than the 3.73. If you rarely go to the track I would not get the 4.10. thats just my opinion.

I;ve got 3.73s going in, in the next month.

i've had both. 4.10s are fine if you have an automatic, otherwise 3.73s for a manual.

i'll be selling my 3.73s in the spring after i get the kenne-bell in and i put my 3.27s in ...

I've had both 3.55s and 3.73s sitting in the garage all summer. Want to put something in over Christmas and still haven't been able to make up my mind.
The All Ford & Mustangs site has pages and pages on the 3.55/3.73 debate and it goes about 50/50 on each.

I'm kind of in the same boat. My '95 is a Saturday night driver mostly but occasional its needed as a highway backup car too. The '95 T-5 has a 3.35 first gear - real low. Like you say with 4.10s you'll fry the tires. Being realistic, for daily driving, even with 3.55s or 3.73s you're out of first gear by 10-15 MPH and I don't think you really want to be much over 2500 cruise RPM at highway speeds. Seems like if you're not looking for bench racing points but real world liveable driving, 3.73s seem like the most you'd want for the street.

At 60 MPH the 3.55s run 1894 RPM in OD and the 3.73s run 1990 RPM. Only 100 RPM difference so I'm leaning towards the 3.73s myself. But,in comparison, my current 3.08s only run 1643 RPM at 60 MPH. That's 350 more RPMs with the 3.73s. Doesn't seem like much. But, a 250 RPM difference in my '66 when I dropped from 3.50s to 3.25s seemed like a giant world of difference better.

I think the key variable on these cars is the overdrive. I had 3.50s in my '66 and it was running about 2800 RPMs at 60 MPH. Almost 4000 RPM by 85 MPH! RPMS were just too high so I put 3.25s in. Just that 250 RPM drop seemed to make a big difference in living with the car on the highway and not feeling like I was beating it to death.

My big questions are 1) 1st gear doesn't last long before you're hitting 2nd with the 3.08s let alone what'll it be like with 3.55s or 3.73 and 2) All the shift points are lowered by 5-10 MPH. You either listen to the engine running faster or you're shifting more and using OD more in town. Would 3.55s really be best??

Guess it comes down to the fact that I can't make up my mind about which gear to use because 1) I'm worried about going to high with the 3.73s for around town but 2) at the same time I want all the bang for the buck I can get and 3.73 is more than 3.55....

Figured I come over to StangNet and see what you guys have for suggestions!

I'm a little wild I use 4.30 gears and a mini spool as well. But with what you are doing the 3.73 should be perfect.

I used to melt my street tires off with 3.73's and just exhaust, intake, and pulleys. After doing the HCI setup it was no longer a problem as the low end torque wasn't as much off idle and it let the tires grip before hitting them too hard with power so that they spun. I can go WOT in 1st (when its warm out) on my nitto DR's and the old 245-50-16 nangkang street tires I used to run. Being a vert helps as we have more weight over the rear tires, and more weight in general which aids in traction. I say 3.73's or even 4.10's at a minimum.

Here's some RPM vs MPH comparison charts I had put together for different gear and transmission combinations. It was originally an EXCEL file but I had to convert it to WORD and then had to split the file into two files in order to be able to upload it. Hopefully this will work....

Torque gets you out of the light and moving down the street. HP is for top end when you're up and moving (ie more important for circle track driving).

So assuming that, on the street, you want the most torque you can get right? (That's why a big block is a big block and small blocks aren't, there's no substitution for cubic inches... that sort of thing). Wont' more gear give you more actual torque "multiplication" and therefore put more torque to the rear wheels?

So for other than nailing the throttle and loosing traction, what's the downside to more gear and more torque multiplication? Baby it out of the gate and then nail it!

My thought is to go with the 3.73s for the most torque. Unless you have some ricer next to you revving his engine and you feel the need to drop the hammer at the light change, most of the time on the street, (at least I myself) will usually roll forward a bit and see what the guy next to me actually does before I nail it. (I'm getting old enough that I usually don't want to look like an idiot and take off when I didn't need to plus I can't afford new tires quite so often anymore).

You might ask how can I be talking about not nailing it? I'm talking strictly street stop light (not track) use. But then again, we are looking for the best street combo right?

With overdrive, you still have decent higher RPMs (3200-3300 at 100 MPH) with the 3.55s or 3.73s. You won't be able to hit 140 MPH on the street with this combo but then that speed on the street is for bench racers or idiots...

Thoughts?

Whats between 3:73 and 4:10 ??

-----> 3:90 gears

Very good ratio. But at that point I would go 4:10's I dont think you'd regret it.

Sometimes, peeps fear of loosing traction if they go to steeper gears is unfounded or at least, a bit over rated. This can be even the more so if they have not .........

1) had a fairly steep ratio
or
2) had a combo that moved the power band up in the rpm range

1. Say you got 308's and take off on a wet road in 2nd gear and loose traction. Your rpms will climb very quickly and you will have to get all the way out of it to recover control.

If you do the same in 1st gear ...... your rpms will not climb as quickly and you most likely can recover control by backing out with just some reduction of throttle.

2. On the very low end of the rpm range you usually don't make as much torque and you usually have a greater rpm range of usuable power.

Gears like 373's or steeper just do not act the same on a h/c/i combo as a stocker. The rpm is the same when in 4th as both combos do have a 1.00 to 1.00 ratio but that is not what I'm trying to explain here.

Another way of saying it is .......

Steep gears on a stocker or combo with a just few mods seem more radical than on a h/c/i combo.

Grady

4.10s, sally. Don't fear the gear. I'd do 3.90's MINIMUM for a street car. It's definately not worth the money to go from 3.55 to 3.73.

For gears and install you could pick up a NOS dry kit!

- Adam

I'll be doing a 4.10 or a 4.30 in my n/a street car. The 3.73 just isn't near enough for my combo. I need to gear the car for where the combo makes power. I need something to get me across the traps around 6,700 rpm.

3.73 should be the minimum gear your typical street stang should have.

Pokageek said:

Grn92LX, that's the answer I am looking for. You have got your car down to a science and know exactly what you want. I will apply this to how I use the car mostly. I will have to play around and see on my own to really get the answer I think.

Click to expand...

Thanks. I want to set my car up to make my combo run to the best of its ability. I do not plan on adding any more power. I want to maximize my combo. The swap to a 4.30 gear (along with all 31 spline stuff in the rear) is a very good move for me. I do want a better tire too.

I think ideally a 4.10 gear would be your best bet for a few reasons. But you already have the 3.55's so use them. Your heavy sn95 convertable can use the extra gear to get out of the hole for normal driving and at the track. You will be faster at the track with the 4.10 and you will cross the traps at the proper rpm with the 4.10's over the 3.55's. Since you don't race the car and don't care for setting it up 100% ideally, the swap may not be the best cost effect move but it would still be a good move.