Rear end gear selection

-
EARLYHEMIBILL

EARLYHEMIBILL

Well-Known Member
Joined
Dec 26, 2009
Messages
114
Reaction score
9
Location
Tucson, Az.
I am building a 67 Valiant with a turbocharged Desoto 352 hemi. It won't be raced, but will be used for a little street scrambling now and then. The car will weigh about 3000 lbs and has a 3000 stall converter. I have 3 different gear sets. 2.23-2.55, and 3.91. The 3.91 is in it now, but I'm not sure if it will be too much. The tires are 275 X 60 X 15s with a diameter of 28-1/2". Any suggestions?
 

Attachments

  • hemi hoses 001.jpg
    61.6 KB · Views: 261
If you go with a lower (numerically) gear, with that 3000 stall you would be under the lock up point, could cause constant slippage when cruising, not good. Excessive heat and transmissions do not get along well at all.

You don't mention what trans, do you have overdrive?

I ran the numbers here: http://vexer.com/automotive-tools/speed-rpm-calculator

and at 60mph you would be just above the 3000rpm mark which is where you would want to be, IMO.

If you DO have OD, then you could get away with a higher gear.
 
Bad Sport said:
If you go with a lower (numerically) gear, with that 3000 stall you would be under the lock up point, could cause constant slippage when cruising, not good. Excessive heat and transmissions do not get along well at all.

You don't mention what trans, do you have overdrive?

I ran the numbers here: http://vexer.com/automotive-tools/speed-rpm-calculator

and at 60mph you would be just above the 3000rpm mark which is where you would want to be, IMO.

If you DO have OD, then you could get away with a higher gear.
Click to expand...
The trans is a 727 that's been well built.
 
That thing is ridiculous. lol I don't like any of them gears. The 2 series are too high and the 3.91 is too low, IMO. I think it would be dead perfect with a 3.23.
 
I am thinking the 3.91's would be the best with the 3000 rpm converter. But it won't be good on the interstate for longer distance. Also around town it might heat up the tranny too much because the rpm's will often drop below 2000 in slower traffic. Not that a well built transmission can't handle a small amount of abuse.
That is going to be radically awesome.
 
chryslerfat said:
I run a 3.23 and think it is the best choice for a street car.
Click to expand...

Probably one of the best street gears, IMO. Long as a good cooler is used, the 3K converter won't hurt a thing with a 3.23.
 
RustyRatRod said:
Probably one of the best street gears, IMO. Long as a good cooler is used, the 3K converter won't hurt a thing with a 3.23.
Click to expand...


Even running below 2500 rpm?

I was always under the impression that they needed to run close to stall, or you would have major slippage.
 
If it is just an off the shelf stall converter, the 3000 number is most likely flash stall. Static stall would be much lower. If this is the case that converter will be fine.
 
Just curious, but what kind of power are you expecting from that engine? I am thinking those 3.23's would be a good starting point.
 
There is someone making them new, I just can't remember who. I will try and find them.
 
Found it. I know nothing about this company but here it is. nitro-gear.com

They only make them for a 742 case from what I read.
 
I plan on running a 355 with a 2800 stall on a mild 340 build in my Dart. Works good in the car its in now.
 
Bad Sport said:
If you go with a lower (numerically) gear, with that 3000 stall you would be under the lock up point, could cause constant slippage when cruising, not good. Excessive heat and transmissions do not get along well at all.

You don't mention what trans, do you have overdrive?

I ran the numbers here: http://vexer.com/automotive-tools/speed-rpm-calculator

and at 60mph you would be just above the 3000rpm mark which is where you would want to be, IMO.

If you DO have OD, then you could get away with a higher gear.
Click to expand...
I'm getting lots of info here and I do appreciate it alot I also have a 2.500 stall converter if you think that will be better.
 
You must log in or register to reply here.
-

Back
Top