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Creating a 4 speed TA transmission

Posted By: sixpackman

Creating a 4 speed TA transmission - 01/14/18 07:31 AM

Hello,

I have an AAR with a incorrect 4 speed trans. Looking for/ create a TA trans. I know the gears are different but the one question I have is the front bearing. Is it suppose to have the big or small bearing to be correct?

Any help would be greatly appreciated.

Thanks in advance.
Posted By: Cab_Burge

Re: Creating a 4 speed TA transmission - 01/14/18 07:49 AM

All of the 1971 and up non overdrive NP 833 23 spline tranny have the same gear ratio as the 1970 AAR and T/A had scope
As far as the front bearings in them I think they where all the smaller 23 spline ones, not like the big hemi bearing and definitely not as big as the later O/D. tranny have scope twocents
Posted By: sixpackman

Re: Creating a 4 speed TA transmission - 01/14/18 10:45 PM

How would I know which trans I have? Is there a specific part number I need to look at to tell me if I have a post 71 trans that has the correct gearing?

I'm having the same issue with the heads on my AAR. I have 915 heads but some are 1.88 and some are 2.02 with offset rockers. The 915 heads have a "A" thru "E" after it? Been trying to figure out how to differentiate between the too. Heads are on my current motor so I cant see the valves.
Posted By: Alaskan_TA

Re: Creating a 4 speed TA transmission - 01/14/18 10:58 PM

Check the partial VIN on your box, there is a date code there on the same pad also. A photo would help.

Measure the front bearing retainer to determine small block or big block.

915 castings all start out the same & then......

Some are built with small valves, some large & some were offset drilled for the intake pushrods for the AARs & T/As.

Post a photo of your heads with the valve covers off too if you want.
Posted By: Cab_Burge

Re: Creating a 4 speed TA transmission - 01/15/18 03:35 AM

On the tranny gear ratio you can put the trans in first gear and mark the input and output shafts and tranny case so you can turn the input shaft and count the amount of turns it takes it to rotate the output shaft one complete revolution, if it takes a little over 2.5 turns it has the 2.66 low gear, if it rotates a little less than 2.5 full turns it has the 2.42 low gear scope
As far as all the original AAR and T/A heads and blocks the heads have the intake pushrod holes move over away from the stock location and all of them have to use offset adjustable rocker arms, they came with them stock with ductile iron adjustable rocker arms and matching pushrods, same cam and lifters as the stock 1970 340 motors had but different rockers and pushrods scope None of them came with the small valve heads, they should be either O or U castings, maybe even some J castings but maybe not on that last one confused
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