lemontwist

I recently obtained a 741 chunk for my 8.75. When talking about an 741 lots of people say, "it won't hold up" however, I don't hear any actual stories or details of 741s being destroyed. If you have a personal experience with a 741 failure I'd like to hear it along with the details. I'd rather not read a bunch of arm chair theory and specs. If you've broken one, I'd like to hear about it.

Coronet 500

If you search Forbbobiesonly or Forabodiesonly this same question many will trash it then you'll find others who have drag raced this with 400-500hp doing 12,11 and10 seconds with no failure. I have not broken one but would not race one with 500hp good slicks and definitely no with a trans brake, on the street no problem.

Iowan

They came in Abodys and pickups, I have a friend running the same gears in his 340 69 4 speed Dart for over 30 years and no failure. I would hate to guess how many times the car has been down the track in that time, it runs mid 12s.

The old Mopar Chassis Book doesn't recommend using the 1-3/8 stem units for high performance applications.......
I would think it's like Dan says how much power and how much traction and the fact you can take you transmission out with the the rear end would make me pass on it. But it depends on the power level and intended use.

RacerHog

I broke 2 of them... Both snapped the drive pinion. Both broken in my 1972 Duster 4/Speed Car.

lemontwist

What engine / horse power did you have? What exactly were you doing with the car at the time they broke? Were you running slicks? Are these the only pinions you've ever snapped?

Iowan

Curiosity got The best of me last night and I called my buddy was the 69 dart, hes got the 742 case, it was in the car when I bought it. He said he had a 741 center in his 62 Plymouth for one weekend and broke it out on the black top.

RacerHog

Not sure what this has to do with "The Price of Milk">>>>> 1- I broke trying to doing a burnout..lol >>>>>>>> The other one was broke, Drag Racing, I think it was about the 3rd pass...
It's a small step pinion. I guess I just "Side stepped" the clutch and it didnt like it. Moved on to bigger and stronger..
But just to answer the question... Yes I have broken the Small Step Pinion Diffs...

RacerHog

I had good luck with my 742 case in my Challenger with the 440... We did out grow it on the performance side, But I never pushed the limit to try and find out what the breaking point was....lol

Iowan

742 weakness is the casting itself behind the caps, you can put billit bearing caps on the center and the casting blows apart. I've only broken ring gears and that was before going to synthetic gearlube.
I don't use a trans brake, 1.40 60' foot brake 3400 lbs race weight

RacerHog

I had some problems with "ProGear" but that was for defects from them.... Also I use to run Torco gear lube back in the day, Or my good stuff from Texas Refinery.. I didn't have really and load issues.. Mostly it would be a part failure....lol

TVLynn

You might find gears will be hard to find MORE options for the 742 & 489 case

lemontwist

Yeah, you're right about limited gear choices for the 741. Fortunately for me I wanted a 3.73 and that was one of the sets readily available. Thanks for the input.