Looking for opinions.

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Skeeter007

Skeeter007

Skeeter007
Joined
Jan 23, 2014
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Barrie Ontario Canada
So here’s where I’m at with my car. I just finished the front end disc upgrade from drums. Full front end rebuild. The car is a 71 Scamp. This car will be seeing in the future a 440/727 combo.
Now in the meantime I need to sort out my rear end. It has the bulletproof 7 1/4 ;-) in it now. It’s got some amazing bearing noises coming from it at highway speed. So I’m thinking to get the 8 3/4 going now. Dr.Diff has some LBP axels on for 295 a pair. Stock length. Go to either the 10 or 11 inch drum and slap it in with the 353 sure grip pig I have sitting here. I’m in talks for a custom length shaft to get me through. Any one do this before? Will drivability be crap? Slant six/904/8 3/4 with 353’s This will also help with a beauty set of rims I’m eyeing.
What do you guys think?

* Is there factory shafts available for this application? Was this set up an option?
 
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As far as drivability goes, every slant I've had has ran great with 3.21, 3.55, or even 3.91 gears. The highway rpm was noticeably different, but the throttle response was so much better with the lower gearing. I imagine there were some 904 & 8-3/4 axle cars, but shortening your current drive shaft and using a conversion joint (if necessary) is probably your easiest option.
 
Is your current drive shaft a 1 pc or 2 pc, will make a difference in shorting ability (IIRC)

As for axle options you can find OEM A Body axles for sale BBP or SBP for around 100 plus shipping, just saw some in the last few days here on FABO,.
 
In the future you will need at least a 8 3/4. I wouldn't put a dime into a 7 1/4. Don't forget springs.
 
Dana67Dart said:
Is your current drive shaft a 1 pc or 2 pc, will make a difference in shorting ability (IIRC)

As for axle options you can find OEM A Body axles for sale BBP or SBP for around 100 plus shipping, just saw some in the last few days here on FABO,.
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I have a set of 8 3/4 SBP. I just don’t want the hassle. I posted my axels on a regional board up here in
 
I doubt there were any factory 225/904/8-3/4 cars... taxis might have 8-3/4s but also had 727s. At any rate it would be so rare that you would never find one. But your plan sounds reasonable.
 
I have seen one '72 Duster Twister that had a 318 & 904 with an 8-3/4 in it but am not sure if the rear axle was factory installed.
 
Anyone know if you can hot tank a pig with the gears still in place. Then re-lube it all before the rust kicks in? My centre section was packed with grease to keep it all nice inside. Now I’m trying to figure out the best way to clean it up and run it without tearing it down.
 
Diesel fuel works really well. Get a metal bucket that the unit can be set on top of with the pinion facing up and fill it a little over half full. Set the pig on top of it with the ring gear immersed above the middle of the adjuster. Put a socket on the the pinion nut and use a heavy duty drill with a 1/2 drive socket adapter and run it backwards and forward repeatedly until clean, spray with fluid film when done.
 
Just do it in an outdoor area away from everything and everybody, there's going to be a lot of vapor and fumes coming up around your drill. An air drill or air ratchet would probably be best, although an impact wrench probably wouldn't hurt anything either.
 
There were lots of darts with the 318/904/8 3/4 combo, its actually pretty common. Not rare at all in my experience
 
It will get real fun when my 440 questions start popping. I’m going to move that conversation over to member restoration section. I can be heavily influenced. Lol
 
replicaracer43 said:
There were lots of darts with the 318/904/8 3/4 combo, its actually pretty common. Not rare at all in my experience
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Especially in 1972! I check every junk 72 that I see. It was the last year for 8 3/4 in an A-body and I've found them under /6 - 904 four door cars. They were just getting rid of stock before they changed to 8 1/4in 73.
 
@Skeeter007 Being that a 440 RB is going into the A body, my questions are;

What kind of power is the engine producing? (HP & Tq.)
What is the main purpose of the car?
What is the cars weight?

The reason I ask these questions is, if your making some serious power on a spirited street strip ride that does see the track, I strongly suggest you consider the DANA 60 since it is much stronger.

By the time you upgrade the 8-3/4 with all new parts and the tricks available for it, it still will not be as strong as the DANA. The 8-3/4 is very capable. This I will not argue. But if you have some good power in the engine and it isn’t a light car and sees track time, in the long run, your not going to be happy.

The 8-3/4 can live in the car on the street a long time. However... if your at the track a bit with it, the car should be very light and the rear braced and upgraded.
 
rumblefish360 said:
@Skeeter007 Being that a 440 RB is going into the A body, my questions are;

What kind of power is the engine producing? (HP & Tq.)
What is the main purpose of the car?
What is the cars weight?

The reason I ask these questions is, if your making some serious power on a spirited street strip ride that does see the track, I strongly suggest you consider the DANA 60 since it is much stronger.

By the time you upgrade the 8-3/4 with all new parts and the tricks available for it, it still will not be as strong as the DANA. The 8-3/4 is very capable. This I will not argue. But if you have some good power in the engine and it isn’t a light car and sees track time, in the long run, your not going to be happy.

The 8-3/4 can live in the car on the street a long time. However... if your at the track a bit with it, the car should be very light and the rear braced and upgraded.
Click to expand...
It won’t see the track. It should be a mild 500-ish hp give or take 50hp. The Dana is an excellent option but I think over kill for what I’ll be needing. Would be cool under there though. I have a housing and pig already with sure grip 3:55 gears. My build will start soon

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