Another Rear End Set Up Question/Advise

[sicndhed]

The 460 is bored .030 over which equates to a 466, right? Trick Flo aluminum heads, Edelbrock Air Gap intake, Q850 carb. Its still at the builder. Working on the drivetrain...or at least getting ready. Found a 3.25 Traction Loc for $200.00 today. Is that a fair deal?

Want a fun driver in the city and a comfortable (as possible) for a highway drive.

I believe it would be 474

If a 460 is 4.36 x 3.85 then I get 466.19 for .030 over and 472.59 for .060 over.

 

[jbojo]

The 460 is bored .030 over which equates to a 466, right? Trick Flo aluminum heads, Edelbrock Air Gap intake, Q850 carb. Its still at the builder. Working on the drivetrain...or at least getting ready. Found a 3.25 Traction Loc for $200.00 today. Is that a fair deal?

Want a fun driver in the city and a comfortable (as possible) for a highway drive.

I believe it would be 474

If a 460 is 4.36 x 3.85 then I get 466.19 for .030 over and 472.59 for .060 over.

My bad, I plugged in a wrong number 466 ci is correct

 

[Luke]

200 would be a Steal in Aus cant help with US price but it Sounds fair

 

[73Vert302]

Sooo...wondering about the 3.25 posi. Fair price?

200 would be a Steal in Aus cant help with US price but it Sounds fair

Thanks...likely will buy it.

 

[jbojo]

Sooo...wondering about the 3.25 posi. Fair price?

200 would be a Steal in Aus cant help with US price but it Sounds fair

Thanks...likely will buy it.

Yeah sounds like a fair price but before you jump on a rear gear size I think that you will need to think of the whole pkg that you are using. You mention C6 so what stall converter will you use? This will be affected by the following.

* Rear Gear Ratio

* Rear Tire Size

* Overall Weight of the Car

* Engine’s Cam Specs: Lift, Duration and Centerline (performance cams usually require higher idle speed)

* Cubic Inches of Your Engine

* Operating RPM Range of the Engine

Would hate to see you put it together and find out you need a different rear ratio or converter because the drive ability is poor for your intended use. A quick call to a performance transmission company with the above info can give you the rear gear ratio that will work best for you. I think that this is a little more critical with automatic than manual transmissions because of the different torque converter stall speeds. I am still trying to learn all of this too.

 

[TommyK]

Really need more info to make any kind of recommendation.

To make 550 HP with 466 cubic inches is going to require GOOD heads (which you have) and a cam with duration @ .050 numbers in the 240's.

IMHO a 3.25 gear and 2000 rpm converter are not well matched to what I think you are building but without more info I am just guessing.

 

[73Vert302]

I spoke to my engine guy and he recommended a 3500 rpm stall converter, said the 3.25 gears "might" work and would be worth a try. His first recommendation was 3.73 ratio. I probably will get the 3.25 and see how it goes. I forgot to ask him the specs on the cam but will post as soon as I talk to him again.

On a side note...I REALLY appreciate the information all of you are sharing. As you can tell I am a newbie to all this and eager to learn. THANKS!

 

[will e]

Swapping rear gears on our fords are pretty easy. If you can get a 3.25 for 200 bucks then you won't lose money if you have to pull it and sell it.

Is this engine going in the beautiful convertible pictured in your avatar? Did it originally have a 302?

 

[luxstang]

A 3.73 will get you off the line fast but it will make for a pretty bad highway cruiser, depending on your transmission ratio.

A friend of mine built a badass 72 coupe with a 460, Keisler 4 speed toploader and 3.73 gears but he ended up hating it because it would rev like crazy on the highway and after an hour of traveling he'd be almost deaf.

So it all depends on what you want from your car.

 

[c9zx]

A 3500 stall speed and a 3.25 gear is a very poor combination. From atop it will feel like the transmission is slipping and it will super heat the transmission fluid rather quickly. Everyone has a different definition of what is streetable but, 3500 stall in a street car is too much with any gear that is streetable. Just my opinion. If you want another opinion call these people http://www.broaderperformance.com. Chuck

 

[73Vert302]

Swapping rear gears on our fords are pretty easy. If you can get a 3.25 for 200 bucks then you won't lose money if you have to pull it and sell it.

Is this engine going in the beautiful convertible pictured in your avatar? Did it originally have a 302?

Yes its going into the Red Convertible. Yanking the 302.

A 3500 stall speed and a 3.25 gear is a very poor combination. From atop it will feel like the transmission is slipping and it will super heat the transmission fluid rather quickly. Everyone has a different definition of what is streetable but, 3500 stall in a street car is too much with any gear that is streetable. Just my opinion. If you want another opinion call these people http://www.broaderperformance.com. Chuck

Thanks Chuck. I will give them a call.

 

[will e]

Yes its going into the Red Convertible. Yanking the 302.

Sweet! I love my convertible and I have a pretty decent running 351c in it but would love a big block.

You are going to need to replace the front springs to deal with the extra weight of the engine. You might consider a thicker sway bar as well.

If you don't already have sub frame connectors then now is the time to add them! That big torque engine is going to try to twist the body every time you get on it.

And you should look at getting some traction bars for the rear as well. I like the under leaf 'Shelby style' as they also assist with braking. Snubber style will help with wheel hop. A cal-trac option is also a good choice. Do some searches on traction bars on this site. (If you look at my garage you can see pics of my traction bars in the modified tab)

3500 stall is pretty high for the street. I would like to know more about the cam specs. A part number or lift/duration would be helpful.

 

[captthundarr]

Is $200.00 fair for the 3.25 posi?

Good price if its in good shape. let me know if you want to get rid of the 2.69 gears

 

[73Vert302]

Actually, from a weight standpoint, my motor will be about the same or less considering the aluminum heads, intake, and water pump. I had a buddy do the calculations and it was less than the stock motor. I was wondering about the "twist" from a convertible so I will look into the sub frame connectors. May do the springs anyway while we are in there. Will look at traction bars as well. Thanks for the suggestions.

Is $200.00 fair for the 3.25 posi?

Good price if its in good shape. let me know if you want to get rid of the 2.69 gears

I may-I will let you know. Gears are in the "WAR" case. Heard good and bad (mostly good) about the war case strength. Most putting it in between Nodular and the standard case.

 

[jbojo]

Just to give you a baseline of what's working of me.

* Rear Gear Ratio = 3.89, when in OD it's equivalent to 3.04

* Rear Tire Size = 26.6" dia

* Overall Weight of the Car = used 3300lbs

* Engine’s Cam Specs: Lift, Duration and Centerline = .525/.555 lift, 290* duration, 222/235* @.50 and 110* lobe center.

* Cubic Inches of Your Engine = 351 bored .030 over

* Operating RPM Range of the cam = 2500 to 6800 rpm (in operating band on the freeway)

* I am estimating low 400 hp with my setup but I don't have actual numbers.

* Stall speed 2800

* C6 tranny

* RPM @ 70 is 3450 without overdrive, 2685 with OD.

As Mike (Luxstang) mentioned the high rpms at freeway speeds can get annoying. I went with a overdrive for the C6 and get 2685 @ 70 mph ( I was getting 3000rpm with 3.25 gears w/o any overdrive). Modern cars today turn around 2000rpm at this speed so not very much difference. With an AOD transmission the same setup would turn 2306rpm because the final drive is .67 vice the .78 that I am using. I know cost is a factor but you may want to consider how many times do you want to pull the motor/tranny to keep changing things around especially if you're paying someone to do it. My suggestion would be that if your car is running good right now wait and buy everything first and then install them. I know its hard to wait when you have a new motor/rear end but I prefer doing things once but sometimes that does not work. Again just my preferences so take this with a grain of salt. Good luck on your mods and look fwd to see how your car performs.

On a side note my car idles at around 800rpm, is very street able in stop/go driving. It doesn't try to die on me at stops and accelerates like my family car does. But when I put the foot into it you feel yourself being pushed into the seat.

 

[73Vert302]

Thanks jbojo, I will use what you have given me and see what I come up with base on my setup. What is your actual tire size?

 

[jbojo]

Thanks jbojo, I will use what you have given me and see what I come up with base on my setup. What is your actual tire size?

I have 245/60/15 in the rear. I will probably go to 255/60/15 when I need new tires.

 

[MotoArts]

I was wondering about the "twist" from a convertible so I will look into the sub frame connectors. May do the springs anyway while we are in there. Will look at traction bars as well. Thanks for the suggestions.

Aside from what I mentioned earlier about the "package" working together, I will recommend subframe connectors for ANY engine in any Mustang.

Even the non-ragtop cars are more flexible than you'd imagine.

When I tied my '90 Fox body convertible with subframes and front strut tower brace, the difference was absolutely night and day. And that car has a stock drivetrain.

Welcome to the Mustang "cash fuse"... it'll keep burning and burning if you let it... LOL!

 

[will e]

I am spending so much on the motor...I need to keep the costs down a little on the drivetrain.

Like motoarts says... it just doesn't work that way. Especially when you build a bad a** motor. But it sure is fun!

 

[73Vert302]

I agree, looks like i really did light the " cash fuse"