741 742 or 489 sure grip

[Arctoad]

Have a question, what is the correct centre section case for the T/A or AAR?

[70 Challenger Lover]

I think it's more a matter of year than model. In 1970, they were using the 489 cases. There may have been exceptions for the early production stuff but I'd say 489.

[RUNCHARGER]

489.

[kathyscuda]

NO ONE KNOWS

[aussiemark]

My late build 70 Challenger has the 489 and I know for a fact it has never been messed with.

[js27]

489 in my 11/20/69 Challenger
JS27

[Arctoad]

Ok,
So with out my Broadcast sheet i'm kinda guessing. It does have the correct leaf springs 3400048 but It has a 741 391 gear set. I'm thinking no way for the 741 to be original that said I haven't taken a pic of the date code but still..
Thanks

[Arctoad]

This is a 1970 T/A forgot to mention that...

[js27]

I do not think any 70's came with a 741 case. My buddy had a 70 T/A he bought from the original owner with 7000 miles and it was untouch. It had a 489 case in it. I know all 3-- 67 GTX I owned all came with the 742 case.
JS27

[Challenger in NC]

489 in my 11/20/69 Challenger
JS27

How do you tell the date on these cases?

[Arctoad]

I don't have any pictures on hand but there is a cast date right below the part number casting.

[HP_Cuda]

It was a generational thing. This comes from a long time mopar mechanic.

The 741/742 case came from older A B and C bodies and trucks. In 1970 they shifted to the 489 case so if you want a correct looking rear chunk you use the 489 case.

Here is a breakdown:
2070742 1.75 " Large 1957-68 B & C
2070741 1.375 " Small 1960-68 A Only
2881489 1.78 " Tapered 1969-74 ALL

[76orangewagon]

Here is a pic of the date code off a AAR 489 case, gears and some of paint inspection marks

[Arctoad]

I guess the good thing is that all of the internals of the 8-3/4 are interchangeable, but now I need to go out and find yet another missing component to my T/A...
As cool as the seventies and eighties were, they were extremely hard and these cars 
Day 2 mods Wow!

[6bblgt]

the gear sets are NOT interchangeable - the sure-grip unit is

& I believe the "741" was used well beyond 1960-'68 A ONLY

"741" was new for '63
"742" was new for '63
"489" was new for '69