Upgrading my Dodge 440 car with a new motor

[Richard Smibert]

The car is a 1964 Dodge 440. I am removing my poly 318 and replacing it with a 440. Should be around 475 HP with the new motor. Transmission is a 727 Auto. What should I be doing with my rear end? Run what I have or upgrade it to something better?

 

[1967coronet440]

What’s in it now, You need at least an 8.75”

 

[Richard Smibert]

What’s in it now, You need at least an 8.75”

I have 2 rear ends. The factory one and I bought another one. The one I bought has a casting #207041. It is a Chrysler 8.75". I do not know the gear ratio yet. I need to get a casting # from my original rear end. More details to follow.

 

[dukeboy_318]

The car is a 1964 Dodge 440. I am removing my poly 318 and replacing it with a 440. Should be around 475 HP with the new motor. Transmission is a 727 Auto. What should I be doing with my rear end? Run what I have or upgrade it to something better?

first, welcome to the forum. I have the same car(see link in my signature below). You should have the 8.75 rear. being a 318 poly, you likely have the 2.76 gear ratio. The biggest thing you might want to do is either convert the flanged axles from the 1964 to the regular style that came in 1965 or modify the the drums to be slip on. theres a couple write ups around here about that. Mainly due to ease of drum brake changes. Pretty easy to do. Either way, the axle should handle that power just fine.

what's your goal for the car? drag? street/strip? cruiser?

Are you keeping the 64 style pushbutton trans?

any pics of the car?

 

[bearman]

I'm doing about the same hp wise and trans. Rear diff coming out going with Dana. Should be a pretty good street car it won't take much more and you will be over 500 hp with all the knowledge these guys and girls have here. Good luck in the project see you on the street.

 

[Glenwood]

I swapped mine with a '70 8-3/4. Keep in mind the overall widths vary through the 60's on B-bodies and I found that I needed to shift the perches on the '70 housing to get better clearance on the driver's side.
The old max wedges were pretty powerful and they used tapered axled 8-3/4" rears which held up well, so unless you are switching to disc brakes, you may not need to change it. You can also order new flanged axles to replace the tapered in the original housing if you want, but you will need new backing plates.

 

[64SF]

I also replaced the flanged axel rear with one out of a 65 Cornet. Swap was easy and even gave me a little more wheel house room. Gear wise I put a 3:23 sure grip in at the same time.