03FstStngKB

^^^ good info...just would like to add to sweet99's post that converters are a must in these cars w/ autos if you want to be able to cut down some ET at the front part of the track. Also I would even think 4.56's would even be doable in these cars for non DD's. The only thing that draws you back with each step up in a steeper gear is that they limit the top speed of these cars(3rd gear) in racing applications unless the use of a taller tire. I have not read anything at all about the 4r70w's being able to be built with a bullet proof OD band? Somethings can be done to prevent it from breaking prematurely, but racing in 4th gear = death at sometime.

RichsDropTopGT

Thanks for all the info guys. I think this will be a big help. I have all winter to play with it now..

RichsDropTopGT

How do you get a pic of your car under your name at your post?

sweet99

Yep, WOT in OD is a tranny killer. Mine is showing some signs of needing a rebuild due to some of that. 4.30's will add about 125rpm's at 65mph or 2625rpm. A 4.56 set-up would raise that to 2775rpm's at 65mph. If you stay within that 65mph speed it's not too bad but I usually end up with traffic at nearly 80mph which is 3000rpm with the 4.10's. With 4.56's you would be at 10% more, 3300rpm, much larger difference than it sounds as 3000rpm with these motors is half of the useable rpm. If you have a second set of tires each inch in height is approximatly a change in gearing by .15 so a 2" taller tire would in effect drop thew 4.56's to a 4.26 gear or 2.98 in OD. THX, Mark

03FstStngKB

Yeah I know I had a 91 5.0 with a built transmission and a transgo shift kit in it. I am not sure if the transgo holds 4th gear for the 4r70w. I do know that it did for my non electronic version of the AOD. My transmission was rebuilt with an "A Servo"...I think one of the most rugged servos for the auto...not sure? I think the Thunderbirds and the Mark VIII's had em also from the factory??? But I was able to hold 4th gear at full throttle. Burned up the gear(band) in less than 2 minutes of aggressive 4th gear(OD) interstate driving at WOT. I could smell the transmission burning from inside the car...who knows how hot the transmission fluid got but I could smell something burning...maybe the band??? I had it rebuilt again...it failed within a month...guy who the put in said it would hold...great guy...just wasn't intune with the transmission weakness?

I was going to say earlier that the good thing about being able to run steeper gears is that you can still run them on the street...and be a stop light warrior, and then run a taller tire at the track to maximize the top end. When you start getting above 3000 rpms...your engine is not going to fail...you are just going to accelerate wear. But if you just had 3.73's and upgraded your torque converter...you are going to match the potential of a steeper gear say like a 4.30 w/o a torque converter. I'm going with best of the both worlds!!!!

sweet99

Changing the 4.30's out hey? I might even go back to the 3.27's if the Hitech stage 2's will run with those gears. I have a new differential here and will sell the complete diff. with the 4.10's if I do. I would have the stall raised to 3800 with my converter first, the torque multiplication was wicked with that stall but the tune I had was bad and the slippage was bad. Now that I have found a great tune for the converter I will be able to go to the 3800rpm again and even higher could be run with the right tune and the ability to hold a WOT lock. My Dirtydogperformance.com converter is Alan's 10" and 3800 is the max it will do. Be sure that the converter you get will hold a WOT lock and get a good tujne and it will seem like a stock converter until you nail it! Then hang on! I would do the converter first and decide upon gears after that. Good luck.

03FstStngKB

I have the 4.30's in already. I just don't have the stall in yet. I am not putting it in till next year after winter. I have a j-mod valve body and a tune ready to go in when I put the converter in. I went with Darrin over at bc-automotive. I have heard nothing but good things from him. To make a long story short if the tune he created for me doesn't work out he will do a live tune in his Indiana shop for me for free. He has another person actually do the tunes but he is wanting to do tunes himself and the look-up tables he has to go by...well he said they don't have much saved for 4.30' geared stangs with that high of a stall? So I won't know how everything is going to play out until next year...but I know when I get the rest of my mods in my sig in...it's going to really make me happy!

jbors1

off the dirtydog website what is the best converter. like 11 inch 9.5 inch and so on. also what stall is recommended for lightly modded to stock 4.6 mustang?

03FstStngKB

Nothing less than 3000 rpms...and would recommend anything between 3200 to 4000...impo. I have heard others say that range to work the best.

sweet99

As far as Alan's site goes ask him! For a stock cammed stang I would get the stock converter reworked. I got mine done for $225-$250. It really woke the car and with the 4.10's would fry my 315 Sumitomo's with a stab of the throttle. Remember the stock stall is about 2600rpm. Don't think so? Find the steepest hill you can and put the shifter in 2nd gear and stab the throttle going up the hill. Where the tach goes to is the flash stall. Mine was 2600. After the rework, furnaced brazed fins, torrington bearings and restalled and it stalled at 2800-3000rpm.
Whether a 10" or 9.5" is best would be deceided by the rpm you will turn. Converters can take only so much before they would break/burst. Alan adds an anti balooning plate to help strengthen the converters. The 10" is good for 6000+ and the 9.5" is good to 6500rpm as I remember Alan's site. I have had the 10" to 6500rpm a few times though When it was stalled at 3800rpm is was wild! I highly recommend the 10" with 3800rpm stall and a tune from Brenspeed. I had a tune from oine of the better known tuners on TCCOA and it was not good at all. My converter slipped in 1st to 3000rpm in regular driving, 2nd gear stayed right at 3000 and finally when it went to 3rrd it would lock and be driveable. Brent asked me what I wanted and locks it 1 seconsd after the shifts at WOT and locks in at part throttle in 2nd gear like 3rd does with a stock tune! I am going to have him have the 1-2 shift occur 500rpm sooner as with 4.10's and the stall I have now(3200-3400) I can leave in 2nd gear and it drives perfect. No bog at all. Then I wikl have a shift & locked converter at about 1700-1900rpm. Brent also did a tune 2 years after I got the Xcal from him 2 years later for FREE, highly recommend him.
I would, again, do a converter first and then decide upon a gear. 4.10/4.30 are reecommended for auto's but the car will rev a bit asas the numbers I showed. i would not want to drive from central NY to Florida with the 4.10's but did do an 800 mile tripo to Virginia and back to get the SVO intake. Testing the stock 192-202* stat again as it seems that the 180* hurt mileage. I'll report the difference. Mark