Third Member and Rear Gear Selection Questions

[Machspeed 219]

Need a little advice here in selecting ring and pinion gear ratio. The engine is a 408 stroker (Windsor Block) with a little over 500 HP/535 ft lb Torque. Trans will be a TKO 600. Car (69 Mach)will be used mainly for show, some cruising, and a few times on the local 1/4 track. Wheels will be 15" Magnum style wheels with applied BFG rubber. From those of you with a similar setup, what would be best all around gear for this combo?

 

Also, I will be replacing the whole third member, as the current unit is a standard 3.00 gear ratio and single axle drive. With this in mind, who would be your supplier....Currie, Strange, etc?

 

Current housing has 28 spline axles and I don't really want to change the axles? Thoughts on this?

 

Lastly, Traction Lock, Detroit Locker, etc? I've recently read something regarding a soft Detroit locker, which seems to contain the best aspects of the TL and DL.

 

Thanks,

 

John

[50dan 25]

Depends what final RPM you desire for highway and street cruising. I use to have a chart that showed cruising RPMs with different gear ratios, you can probably find one online. Sounds like a great setup. You might be able to run a 4.30 and have tons of street torque and then nice cruising at highway speeds. That would be perfect to me anyway.

 

I bought a new Auburn TL for mine. Lockers are more for striaght line.

Edited July 6, 2012 by 50dan

[sportsroof69 13]

A few things to consider..

 

You do have overdrive, so you could run a lower gear, BUT you're running BFGs, on the street, with power. You'll never get them to hook, so the gear is wasted. I have those tires on my street wheels, and I switch them at the track, and I can tell you that if you get into at all, they make no attempt to stick. If it were me, I'd look into something like a 3.70 gear.

 

As far as axles, Moser makes a direct fit set of 31 splines for our cars. I use them in mine, and they work great. You say you don't want want to change them though, and that would be okay IMO because again, your on street tires. It will never hook good enough to hurt the stock 28 splines. I ran the stock 28 splines at the track for a year, on slicks, and it had just put a very slight twist on the splines, but I was hooking it up.

 

I use a Detroit locker, because I don't mind putting up with it. It is noisy in the turns, but it's just part of it.

[buening 63]

Do you have the standard TKO or the road race version? They have different gear ratios, effecting your final drive ratio.

[69gmachine 15]

I have a very similar set up. I'm running 3:70s and I believe the 2:70 1st gear in my TKO (or something pretty close). I think the 3:70s are a great all around gear for a 408. If I was to spend a lot of time on the highway going over 70 mph, then I would go with 3:50s, but for what you're planning (and how most of us use our vintage cars) I think 3:70s would be perfect.

[Machspeed 219]

Hey thanks guys.......

 

Trans is the standard TKO, buening.

 

Looks like the consensus is 3:70 and this is exactly the gear ratio I was considering. 69g, what rpm are you looking at around 70 mph?

 

sportsroof, fellow Okie, I see your down the road from me in Ada. Did you make the Mid American Mustang Shelby Meet a few weeks back? I was there but do not recall seeing your Mustang. Which, btw, rocks!!! Wow, just noted your youtube video.....most impressive launch!!! Mind if I send you a PM?

 

Thanks again friends,

 

John

[MaxLT 10]

I've been trying for 15 years to blow up my little 8" 2.79 rear end so I could justify the cost of a good 9" upgrade and don't you know it, the darn things bulletproof and just keeps taking all the abuse I throw at it.

 

When it finally goes I figure anywhere between 3.5-3.7 is just about right for my TKO-500 and 408W street rod.

[sportsroof69 13]

Hey thanks guys.......

 

Trans is the standard TKO, buening.

 

Looks like the consensus is 3:70 and this is exactly the gear ratio I was considering. 69g, what rpm are you looking at around 70 mph?

 

sportsroof, fellow Okie, I see your down the road from me in Ada. Did you make the Mid American Mustang Shelby Meet a few weeks back? I was there but do not recall seeing your Mustang. Which, btw, rocks!!! Wow, just noted your youtube video.....most impressive launch!!! Mind if I send you a PM?

 

Thanks again friends,

 

John

 

Thanks! Feel free to send a pm. I noticed you were an okie as well.

 

This is the first year I haven't attended the meet in quite some time, though I've never taken my car anyways. I usually just drool at the others.

[69gmachine 15]

69g, what rpm are you looking at around 70 mph?

 

John

 

 

Using the RPM calculator on Corral.net, I should be turning approx 2300 RPM in 5th gear at 70 mph with P275-40 tires.

 

Since my tach is dead I can't just go out and confirm it, but it sounds reasonable.

[maxum96 32]

I run a 393W (550hp-600hp) with a TKO and a 4.11 gears. I turn about 2000 rpm at 60 mph. And as sportsroof69 commented about BFG tires, I look at the throttle and my BFG's start smoking. But I didn't put them on for performance. I put them on for appearance. I would recommend a gear between 3.50-4.11. I think 3.91 gear would be optimal in your case.

Edited July 7, 2012 by maxum96

[sportsroof69 13]

Yep. You can't beat the look of the BFGs. That's why I have them too.

[PaleRider 12]

Yep. You can't beat the look of the BFGs. That's why I have them too.

 

Plus the smoke they make when you light them up is impressive :clown:

[coz 108]

My setup works real well and would be perfect for you... I also have a TKO600 with the .68 5th gear. I wish I had selected the .82 version....

 

Moser 31" spline axles

Moser Center with TruTrac and 3.90 gears

28" tire (275/60/15)

 

With a taller tire you'll want the 3.90 gear. I run 2200rpm at 70mph down the highway.

 

Like everyone says, BFGs will not cut it. Go to a MT ET Radial or Hoosier Street slicks. Both work fine on dry payment and will hook (somewhat) when you get into it. Look into traction bars - I like my Cal-tracs.

 

Everything works great on the street and even better off the light...

[Machspeed 219]

Hey Friends, thanks for the input. After much research and consideration, I went with 3:89 gears, Detroit Locker equipped for 31 spline axles all loaded in a Nodular case. Now I need to buy axles......never ends, does it?

[buening 63]

Exactly what I have planned, except I may go with the TrueTrac. Let me know if you find a decent deal on axles. I believe Superior axles were the best bang for the buck from Summit Racing (which I think is the correct ones below).

 

http://www.summitracing.com/parts/SAG-PA6070D/

 

http://www.summitracing.com/parts/SAG-PA6070C/

[Black_69_FB 49]

Exactly what I have planned, except I may go with the TrueTrac. Let me know if you find a decent deal on axles. I believe Superior axles were the best bang for the buck from Summit Racing (which I think is the correct ones below).

 

http://www.summitracing.com/parts/SAG-PA6070D/

 

http://www.summitracing.com/parts/SAG-PA6070C/

 

Those are the axles I used when I upgraded to 31 spline last fall.

 

Bought the center section/gears all set up & ready to pop in from a place in N. Carolina called Nine Inch Nodular. I think I still have his contact info if anyone needs it.