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Old 02-13-2015, 08:33 AM
Krooser Krooser is offline
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Location: Central WI
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Default Any 8.75 gear experts here?

Here's the deal… I have a dirt super stock that I'm rebuilding and it's an all Mopar drivetrain deal. I have a couple 741 chunks but I need a 4.10 and maybe 1 4.30 gear for the tracks I'll be running… gears for the 741 in those ratios are impossible to find.

Now the real question… is there any good reason I couldn't turn down the stem on a set of 742 gears from the 1.75 diameter to the 741's 1.375 size? The 741 will be plenty strong enough for my car. Most guys use 9" rear but the Mopar is lighter and takes less HP to turn. And my budget is non-existant so I need to use what I already have on the shelf.

I have two good machine shops that I could hire to do the work. I know these gears are heat treated… machining them wouldn't change the heat treat but may make it a bit tougher… I'll have to ask about that. My concern was the diameter of the pinion stem… are they the same between the 741 and 742? If the only difference is the stem diameter it would be much cheaper for me to have this work done to the pinion.

I need to make the 742 gear on the right look like the 741 gear in the middle...

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Old 02-13-2015, 08:45 PM
70Ted 70Ted is offline
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would be easier to use the 742 or 489 center??
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Old 02-14-2015, 07:53 PM
Krooser Krooser is offline
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Yes… but I already have two 741's, two racer friendly machine shops that will work for beer and a zero budget. If I don't get it done cheap I don't race… that's not an option. Eventually I'll have three ratios available… 3.91/4.10/4.30 for just about any track I would ever run.

I talked to one of my buddies and he thinks only the gear is heat treated… the stem should machine pretty easily. My son is getting the new gears for me so I should have a set in my hands in a couple of weeks… then we'll do more investigating.

Look at it this way… if this works it opens up a whole new world of available gear ratios for anyone with a 741 pumpkin instead of being saddled with 3.55 and 3.73 ratios.
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