stall converter info

zapc

Daily Driver
Dec 8, 2010
14
0
0
hey guys

i just swapped a 496 and a turbo 400 with a 2500 stall converter in my elcamino.
i need to to swap gears in the rear to finish up this car. am i correct in thinking that i have to select a gear that will be turning at least 2500 rpm at my desired highway speed or else the converter will never lock and ill burn up the converter and transmission?

with a 29" tire at 65 mph a 3:42 or a 3:53 will put me in the ballpark.

thanx

chris
 

SSedan64

Dragway Regular
Oct 5, 2009
948
0
0
MACON, GA.
With that mild of a Stall rating it shouldn't be a problem. It's always a good idea to add an external Trans cooler tho'.
The rear gearing should keep your cruising rpm within your Cam's power range for better mpg, keeps the Carb out of the enrichment circuit.
 

zapc

Daily Driver
Thread starter
Dec 8, 2010
14
0
0
thanx i just keep reading that the transmission will overheat if it doesnt reach lockup rpm
 

SSedan64

Dragway Regular
Oct 5, 2009
948
0
0
MACON, GA.
Unless you have a Converter with a Lockup Clutch there's always some slippage. Depending on how efficient the Converter couples at it can range from about 3% to 20% at upper rpm range.
The 2500rpm stall rating is under a heavy load, Braking stall or Flash stall. Just cruising under a very mild load it isn't going to be slipping/stalling much. If you had a 3000, 3500 or higher stall rating it can be a problem.
You can install a Temp sensor in the Pan to keep an eye on things if you want. Some install sensors inline in the Cooler line to Radiator or external Cooler. This will not give an average Trans temp as the fluid coming out of the Converter goes straight to the Cooler & will be much hotter than what's in the Pan.
 

zapc

Daily Driver
Thread starter
Dec 8, 2010
14
0
0
thanx for the info, im gonna add a real big transcooler and hope for the best, i probably should have stayed with a stock converter,
 

monte ss496

Dragway Regular
May 23, 2010
1,358
0
0
western mass
why not try 3.73's?
 

zapc

Daily Driver
Thread starter
Dec 8, 2010
14
0
0
that will put me arround 3000rpm at 65 a little high for cruising no?
ive had such horrible luck with overdrive trannys that with this much hp, i have no confidence in an overdrive transmission. i know some rave about them. ive blown up every 700r4 i ever had.never had a 2004r though
 

SSedan64

Dragway Regular
Oct 5, 2009
948
0
0
MACON, GA.
With that 496 a 3.42 or numerically lower gear should be fine.
Good calculator here>> http://www.f-body.org/gears/
TH400, 29" tire, 3.42 = 2600rpm @66mph, add about 200rpm for TC slippage = 2800rpm.
3.23 gear = 2400rpm @64mph + 200rpm slip = 2600rpm
1st = 2.48
2nd = 1.48
3rd = 1.00
A GV/Gear Vendors OD would be nice. :) 25% OD

What type Rear are you using? 8.5"/10-Bolt, 8.875"12-Bolt, 9" Ford?
 

zapc

Daily Driver
Thread starter
Dec 8, 2010
14
0
0
motor should be arround 550hp, i only have 2.42's right now in the rear and its really weird to drive cause the converter is always slipping i guess, seems im always at 2,500-2,800 all the time while crusing no matter what speed im going above 40mph. even with 2.42's motor is still a monster, punch it at 30 and the tires go up in smoke. not gonna drag race car on the track. just a street toy. really want to do a 9" rear but i have a chance of getting a grandnational rear with 3.73's for $500. ill try that untill i get the money for the 9"
 

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