Rearend ID

[wazoo64]

I am finally getting the gear vendors install going and plan on changing the rearend from 3.23 to 3.73. The tranny guy says that the 8 3/4 has different types of 3rd members and the one I have will not accept 3.73 gears. Anyone have some clarification on this? My guy is telling me that I will need a different 3rd member to make this happen. What are two types of 8 3/4? How do you identify them?

 

[res1vw21]

Look at the case there should be some #s that end three different ways. 489, 742, 741
anyway her are some websites that tell you a little bit about them
http://www.autohobbydigest.com/8_75.html
http://members.tripod.com/~Mojo_Page/chry875.htm
http://www.moparmusclemagazine.com/howto/155_0308_mopar_rear_end_gears_set_up/index.html
http://www.dodgepolara.com/rear.txt
http://www.planethoustonamx.com/main/chrysler_8_34_rearends.htm
Hope this helps

 

[wazoo64]

Perfect ....Thanks

 

[damnimcooltom]

Last time I checked the 3.73 gearset was only avalaible for the 741 case. It's been a couple of years since I checked, but that's probably what your guy is talking about.

 

[wazoo64]

Found out that I have a 741 with 3.23 gears. I am having the 3.73 ring and pinion installed. Will this hold up well on 450+ HP? I was told the 741 was designed for 6cylinder HP. Any thoughts?

 

[damnimcooltom]

Automatic or manual transmission? I've known people to break the 741 pinion with a manual, but not an automatic. Make sure all of the components are good quality and setup correctly, and you should be fine with an auto.. Are you going to be drag racing?

 

[wazoo64]

Auto with gear vendors....street use only. Thanks

 

[sublimeswinger]

You should be fine. My buddy has a 741 behind his 400+hp 360 and has had noo problems. Its not the most desireible unit, compared to the 742 and 489, but it will work.

 

[demon seed]

Found out that I have a 741 with 3.23 gears. I am having the 3.73 ring and pinion installed. Will this hold up well on 450+ HP? I was told the 741 was designed for 6cylinder HP. Any thoughts?

You'll do fine with the 741, hell I ran many of them and who ever told you that they were for 6 cylinder HP you can tell him for me to get his head out of his :bootysha: and go back to Chebby's. LOL

 

[fishy68]

I agree also. The 741 is under rated by allot of guys. It isn't as strong as the 742 or 489 but it's still pretty stout.

Also just for every ones info 3:73 gears can be had for any case now. I've seen them listed for 741's and 489's for quite a while but couldn't get them for my 742. I just found that Gears-R-Us stocks them in the Motive Gear line. I just bought a set and they were $210 shipped.

 

[fishy68]

You'll do fine with the 741, hell I ran many of them and who ever told you that they were for 6 cylinder HP you can tell him for me to get his head out of his :bootysha: and go back to Chebby's. LOL

Terry's exactly right. The 8-3/4 wasn't even used behind a 6 cyl. The 7-1/4 was the common rear behind 6 cyl's with the 8-1/4 being the optional HD rear end.

 

[damnimcooltom]

8.25s and 8.75s were not used in A Bodies during the same years. The 8.75s were used until 72, and the 8.25s were used 73+. A slant six and 8.75 could be found in the same car, but usually only with a manual transmission.