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741 Question???

westie47

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A buddy has a 3.91 741 case center section that I am thinking about buying. I believe it is a small pinion, but not sure how to tell. The only issue is that it isn't a Sure-grip so I'll need to buy a True-Trac or something similar. My driveshaft is small pinion (both ends have a taper). The driveshaft fits with the 741. The current center section is out of a 58 or 59 8 3/4.

My question is if it's too small for the power I'm making. My 440 is dyno'd at 450 hp/538 lbs-ft. I have a 2400 stall and shift kit in the 727.

I don't know alot about rear ends, any advice helps.
 
Never seen a broken pinion in a 41 case 8 3/4.....unless it was shaved teeth and I seen that with all of them be it a 41 or not.
 
http://www.doctordiff.com/blog/tech-info/rearend-pinion-comparison/

On street tires and an auto transmission, you will have no problems. They start to break when you have a manual transmission and the tires have good grip (slicks). Had a 741 - 3.91 gears in a 70 Challenger 440 and a 727 on BFG street tires. I beat on that car for 5 years and never had a problem.
 
A 741 is the small pinion case, and as such has a poor new r&p selection. However, if you are happy with the 3.91s, that shouldn't be a problem.
Any carrier will interchange in any 8 3/4 case, so you can put any sort of sure grip you want in it, cone, clutch, truetrack, or spool. (Wouldn't recommend the spool)
As for the undeserved "weak" reputation, see Dr Diffs site for a comparison of the pinions. They are NOT a weak point.
As with any 8 3/4, street tires will never be a problem. LOTS of horsepower, slicks, and a four speed, there are better answers. With a street tire and a 727, you'll be fine.
Edit: the unit in there now is also a small pinion.
 
One of my cars has a 741 suregrip behind a mild built 440 probably close to the hp your talking about. Its been 20 years now and countless burnouts with no problems so far.
 
Do you plan on running it at the track with slicks? Are your horsepower figures a crankshaft number?
I want to take it to the track once or twice but it’s mainly a street car.
Yes that’s at the crank. I dyno’d the engine on a stand.
 
I want to take it to the track once or twice but it’s mainly a street car.
Yes that’s at the crank. I dyno’d the engine on a stand.
I wouldn't have any problems with running it.....but the price can't be the same as the 42's and 89's.
 
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