8 1/4 or 8 3/4

[steve from staten island]

Since I have a sure grip from a 66 b body which seems to be in decent shape I was thinking of having that rebuilt and using it in my 69
My car currently has a 8 1/4 open rear with 2:73 gears.
Ive read numerous accounts that the 8 1/4 should be more than adequate for a 69 b body with a 383 producing under 400HP and most likely will never be taken to the track.
Also no burnouts or anything remotely like that.
So added in the cost of a sure grip and new gears, say 3:23, would it make more sense just. to rebuild the original rear or continue to go with the. 8 3/4
The rear while it seems ok is the last part of my car not gone over and so I want to tackle that this winter. The car is ok but could benefit from lower gearing
I had the car on the highway and was doing about. 50-55, the car was just cruising along leisurely and it seemed like I hardly had my foot on the gas pedal, almost like it had over drive

 

[WP29440SE]

the 8 1/4 is plenty fine for your intended purpose. I've been running one for years behind my 440. I have an 8 3/4 just sitting but I can't seem to break the 8 1/4

 

[Jerry Hall]

A 8 3/4 is definitely a stronger gear, but the way you describe your use of the car the 8 1/4 will give you good service and added gas mileage that you may not want to give up. If you're looking for added pep (acceleration) then your right foot is not as light as you would want us to think. Personally my right foot tends to stress everything. That's why I bought my first Mopar in 67. It's like the Timex watch commercial, it takes a beating and keeps on ticking.

 

[HALIFAXHOPS]

Look around for a jeep dana 35 they arfe cheap to steal the sure grip from

 

[beanhead]

Your 8-1/4 will handle the power, for sure, but if you're talking rebuilding it...I would switch to the 8-3/4, not as much because you need the strength but for the added benefit of the sure-grip. If you're thinking of rebuilding it anyway, that is...it's a chunk of cash either way. 3.23 will still be a nice cruising gear, and you'd feel a little more pep with those and the sure-grip diff.

 

[wagonman]

I have a 73 Duster with the 8 1/4 321s and a SG from a 96 Dakota. It is behind a 470 727 combo. The only parts that seem the weak link are the 27 spline axles. so far so good with Cooper 275-60-15 but NO Slicks ever.

 

[steve from staten island]

Im not going to ever do anything that I see is stupid on the street. I thought since I had the 8 3/4 why not use it, especially that it has 355 gears.
I had a 69 GTO with the 350 HP engine. It had 355 gears and I found that to be a nice ratio. Since the HP in the GTO and my present. car are close to the same was another reason.
I will be talking to the rebuilder soon to get his opinion....Thanks

 

[Dibbons]

I kept my 8 1/4 with 2.73 gears but added a sure-grip (used). I am happy about it. Running the original 318 for now, but a 340 is definitely in the future. With the bigger V-8, I am not going to change out anything in the rear end.

 

[Dibbons]

Correction to post #8: I believe the 8 1/4 is equipped with 2.71 gears (not 2.73).

 

[dana44]

Look around for a jeep dana 35 they arfe cheap to steal the sure grip from

If you want to rob a jeep axle the xj's are comman to have an 8 1/4