Opinions on 3.89 gears or ??

[Thumperbird]

"Sorry - this makes no sense at all.  The converter does not control the shift points - unless you have a manual valve body, those will be determined by the valve body programming and the governor.   If the converter is way loose, then I think that may be what you are saying - RPMs will "wing" and the trans will shift at whatever RPM it is set for."

Communication breakdown...
All I was trying to say was why run more gear and higher stall if just a street car and low rpm launch still spins tires significantly into 2nd gear.  Followed by if you get a bug for speed and you have plenty of hp/torque then you may want to reconsider if suspension and tire upgrades are in the future.

[cammerfe]

When I ordered my '64 Custom/427, I had a choice of a 4.11 or a 3.50. So I ordered the 4.11. I soon found out that the 4.11 was just fine for running around town, but I needed a 3.50 for highway cruising. I put a set of 8.20X15 tires on the rear, and made a little chart that I taped to the dash. 3000 was about 70 in 4th gear.

The nice thing about the 3.50 was that I could shift back into 3rd at 100 and have a serious passing gear---or just the thing for dealing with 'vettes and 409 chibrolays on the highways. And with the 3.50, 2nd gear was just great for roll-racing around home. Higher-numerical-geared cars were wanting to be in 3rd but I had very usable RPMs left to enable me to get a jump.

I had a top speed of over 150 with the highway combo, but the steering got very light starting at about 130. (The speedo only went to 120, but the needle would show in the 'gen' red light next to the 120 line on the dash.)

KS

KS

[plovett]

When I ordered my '64 Custom/427, I had a choice of a 4.11 or a 3.50. So I ordered the 4.11. I soon found out that the 4.11 was just fine for running around town, but I needed a 3.50 for highway cruising. I put a set of 8.20X15 tires on the rear, and made a little chart that I taped to the dash. 3000 was about 70 in 4th gear.

The nice thing about the 3.50 was that I could shift back into 3rd at 100 and have a serious passing gear---or just the thing for dealing with 'vettes and 409 chibrolays on the highways. And with the 3.50, 2nd gear was just great for roll-racing around home. Higher-numerical-geared cars were wanting to be in 3rd but I had very usable RPMs left to enable me to get a jump.

I had a top speed of over 150 with the highway combo, but the steering got very light starting at about 130. (The speedo only went to 120, but the needle would show in the 'gen' red light next to the 120 line on the dash.)

KS

KS

Well, if you hit 150 mph, then it sounds like you were running about 6500 rpm.  That sounds very plausible to me, and fun.   

I had a Porsche 914 once (I know, weak), but it would go 120 mph.  It was the 2 liter version.  The front end felt like it was off the ground at that speed.   It needed an air dam SO bad. 

I had my '66 Fairlane GTA (with a 428CJ) up to 145 mph and it felt much more stable.

paulie

[plovett]

double post. sorry

[machoneman]

double post. sorry

I can tell you that my '70 Stang (and '69's as well) does get light in the front at over 130 or so. I know, others here have not had this happen but my SBF with a a lot of light weight parts (heads, intake, pump, P/S delete and much more lightening) does get scary light. It's the shark-nosed front end with the taper facing the wrong way (pushes up) that even with the factory air dam gets way too much air under the front. A SCCA pal noted that others (all light weight fronts w/SBF power ) have had similar issues, some at nearing 145-150. A clue is the massive front air dams Ford used in the famed '69-'70 Trans-Am series where the bottom of the dam nearly touched the ground (think: Bud Moore prepped cars). That under-the-chin "lift spoiler" was big for a reason!

[Falcon67]

"Sorry - this makes no sense at all.  The converter does not control the shift points - unless you have a manual valve body, those will be determined by the valve body programming and the governor.   If the converter is way loose, then I think that may be what you are saying - RPMs will "wing" and the trans will shift at whatever RPM it is set for."

Communication breakdown...
All I was trying to say was why run more gear and higher stall if just a street car and low rpm launch still spins tires significantly into 2nd gear.  Followed by if you get a bug for speed and you have plenty of hp/torque then you may want to reconsider if suspension and tire upgrades are in the future.

Well said - sorry for the miss-communication.

[cammerfe]

double post. sorry

I can tell you that my '70 Stang (and '69's as well) does get light in the front at over 130 or so. I know, others here have not had this happen but my SBF with a a lot of light weight parts (heads, intake, pump, P/S delete and much more lightening) does get scary light. It's the shark-nosed front end with the taper facing the wrong way (pushes up) that even with the factory air dam gets way too much air under the front. A SCCA pal noted that others (all light weight fronts w/SBF power ) have had similar issues, some at nearing 145-150. A clue is the massive front air dams Ford used in the famed '69-'70 Trans-Am series where the bottom of the dam nearly touched the ground (think: Bud Moore prepped cars). That under-the-chin "lift spoiler" was big for a reason!

One thing I didn't mention before was that I used spring jacks in the front coils (the kind that you put between the turns and then screw apart to open the spacing). The idea was to get a bit of 'squat' in the back to help weight transfer. With Traction Master bars in the back and 8" M&H Dragsters on it, the traction was pretty good, but it let the air get under the front quite easily.

I was dating a girl who lived in a North Western suburb of Detroit, who was going to Michigan State in East Lansing. Her Dad would get her on Friday night, but I'd drive her back Sunday evening. I was coming home about midnight, one Sunday night, running on I-96, with nobody around. Then I saw headlights behind me. I was doing about 75, and he was doing about 80. When he got even, I saw it was a 'Vette, and as he started to go past, I nudged it up to about 85. and then he... At about 100, and even up, I made an emphatic downshift to third and stomped it. I wound it out before shifting back to fourth. I'd pulled him pretty good, but he didn't quit, so I stayed in it. As I said above, the speedo needle would show in the red 'gen' light, probably at about 130-135. I did take it to about 6500 before I quit, and he was just little lights in the distance behind me. But I was steering with only one finger and thumb on each hand so as to not put too much emphasis on the steering wheel. Luckily, the E-way was straight in that area because the wheel was giving almost NO input. Hopefully, I'm a bit smarter by this time.

Getting ready for ECTA with my Lincoln LS, I found that the top speed was also over 150, but that the best I could do in one mile from a dead stop, was 140.106. And that was with the help of a competition kit from NX, who sponsor me, and using methanol with the spray instead of gasoline. The kit was sized to give 400 HP+ with gasoline but I only had nominal 'pills' in it for 100, and I didn't turn it on until I went into third gear, to save the trans internals. That set the record, which I hold to this day.

KS

[AlanCasida]

If I wasn't planning on taking it to the track I'd put a 3.25 gear in it and enjoy cruising in it...but that's just me. 

[My427stang]

I like the idea of the 3.89 with the 29 inch tall tire.  Does the engine have the oats to let it rev a little when you want to play?

3.89 sounds a little deep, but it isn't far off a car with 245/60s and a 3.50 gear.  All depends on the build, if real stock, I might go for the calm behavior of less gear, but if it's a little ornery, go for it    

[machoneman]

I like the idea of the 3.89 with the 29 inch tall tire.  Does the engine have the oats to let it rev a little when you want to play?

3.89 sounds a little deep, but it isn't far off a car with 245/60s and a 3.50 gear.  All depends on the build, if real stock, I might go for the calm behavior of less gear, but if it's a little ornery, go for it

I like the 3.89's as well but note that a lot depends on your driving experience. If in a rural area and/or with lots of highway driving, it's a lot of rpms. But if it's limited highway and lots of stop and go driving (say, in urban areas) they should work great.

[winr1]

Thanks for all the replys guys 

My Friend who builds 9" 3rd members is sellin me a nice used 3.50 ring an pinion for $50.00

As said above, I can go to some shorter/wider rear tires to change the ratio up a bit

Now to decide between a 4 speed or auto..... lol ..



Ricky.