rear gear question

[steel1212]

If I was to get rid of my 4.11s and drop to something taller for better streetablitly what kind of lose would that be in my times at the track? The 4.11s are ok for now I'm just checking my options for when I rebuild my rear and go to 31 spline.

 

[302 coupe]

I like my 3.70's, turn about 3000 rpm at 55-60 mph (C4 trans). Speedo is off, and the converter is fairly loose, so its hard to get an accurate number.

 

[chepsk8]

Need more info! What motor mods, use, etc. Why not put in a AOD or T-5, so you can keep the gears for good acceleration, then drop into OD for the highway?

 

[thehueypilot]

If I was to get rid of my 4.11s and drop to something taller for better streetablitly what kind of lose would that be in my times at the track? The 4.11s are ok for now I'm just checking my options for when I rebuild my rear and go to 31 spline.

I'm getting ready to do the same thing going from 4.11 to 3.55 but because of traction problems. You will lose 60' time which will lower your ET. It also depends on how high/quick you have to rev your motor to find the best shift point.

 

[steel1212]

I have a t-5 thats why they don't really bug me to much right now. I would just like a little more out of each gear before I get to OD. Also I'll be hitting the juice a little a bit and think I might run out of gear.

 

[thehueypilot]

I cross the 1/4 mile stripe at 6540 rpm and at 6750rpm the valves start to float and that’s all in third gear. My OD is electrically activated so it is always switched off when I race.

 

[DarkoStoj]

4.56 and tremec 5 speed here

 

[steel1212]

Whats your trap rpms with the juice? I may not switch from the 4.11s...don't really want to

Huey I don't have your kind of torque so once I get cal-tracs hopefully I won't have any traction problems with just a 100 shot.

 

[iskwezm]

4.56 and tremec 5 speed here

how does that run at about 70mph???I have 3.80's and need more gear for this cam that im using

 

[steel1212]

I have the 0.63 overdrive gear and I think it comes around 2300-2400 rpms. I'm not 100% as I have to fix the speedo gear in my tranny so my speedo isn't working right now.

 

[351carlo]

I cross the 1/4 mile stripe at 6540 rpm and at 6750rpm the valves start to float and that’s all in third gear. My OD is electrically activated so it is always switched off when I race.

What tire size are you running?

You're trapping 112 which makes me think you're only running a 26 inch tire.

Ever tried a 28? I've got a similar setup revving setup and haven't brought it to the track yet with the 4.11's. I know I'm going to run out of gear on the 125 shot, but I'm just gonna let off at the 1000' mark anyway.

 

[thehueypilot]

What tire size are you running?

You're trapping 112 which makes me think you're only running a 26 inch tire.

Ever tried a 28? I've got a similar setup revving setup and haven't brought it to the track yet with the 4.11's. I know I'm going to run out of gear on the 125 shot, but I'm just gonna let off at the 1000' mark anyway.

You are correct I am running a 26 inch tire. The 28 would not fit unless I bought new rims with a greater offset moving the tire more inboard. That's in next years budget.

 

[HistoricMustang]

I'm getting ready to do the same thing going from 4.11 to 3.55 but because of traction problems. You will lose 60' time which will lower your ET. It also depends on how high/quick you have to rev your motor to find the best shift point.

Yep, the 3.55's make a great street gear.

HistoricMustang
www.historicmustang.com