8 3/4 choice for a '69

[doctor4766]

Time to upgrade to an 8 3/4.
Mostly to get a better ratio but having a stronger diff will be a bonus.
I currently have the original rear axle setup. Being a 318 car originally it has I believe an 8 1/4 2.76
Since I'm now running the big block, freshly rebuilt, I thought I could get some advantage from converting to a 3.23 ratio.
Only problem I have is that my mate (who has a few 8 3/4's available) reckons my 295/50/15 tires on 8 1/2" Vector rims will be an issue if we do the axle swap and that I'll have to run the 7" rims with the 255's I have so they'll fit.
Can anyone verify this?
I'd like to keep my big wheels, so what casing do I need to be looking for and how wide should it need to be in order that my wheels don't rub in the wrong places?
I might point out that all his 8 3/4's have come from late 60's to early 70's Australian Dodge Phoenixes (Polara's to you guys)
Any suggestions would be appreciated.
 

[Ghoste]

I think in your case any version of the 8.75 will be strong enough.  As for your other questions, I don't know.

[ACUDANUT]

Those rims should fit, as long as the wheels have the standard 4 or 4 1/2 inch backspacing...Either way, you need that 8 3/4 with a Big Block. 

[charge69]

It is  possible that the 8 3/4' rear is longer than the stock unit. I would definitely measure. The spring perches might have to be moved too.

[c00nhunterjoe]

Double check what you have first, my car is origonally a 318 car and it was equipped with an 8 3\4. I had 7 inch wheels with 275\60\15's on it with tons of room for bigger tires. I just swapped to 8.5 vectors but they are spaced out slightly and the 275's are as big as I can go. I will measure the backspace on my vectors to let you know what they are

[doctor4766]

It actually looks most similar to the 8 3/4" in this pic from another current thread, but I'm sure I've seen a tag saying 8 1/4



Now the housings my friend has are C body and yes we can relocate the mounting brackets so hopefully one of them will be close enough in width to fit under my Charger.
I'm guessing I'll need to change the tailshaft as well?

[c00nhunterjoe]

If it has a rear cover its not an 8 3\4 but I didn't think they had another option for 69 chargers.

[doctor4766]

Looked under there today and yes there are bolts holding a cover on but other than that it doesn't look like ANY of those other pics.

[Ghoste]

Maybe you should shoot us a pic.

[doctor4766]

Yeah will do if I can get my piece of crap Nokia working.

[1969chargerrtse]

It actually looks most similar to the 8 3/4" in this pic from another current thread, but I'm sure I've seen a tag saying 8 1/4



Now the housings my friend has are C body and yes we can relocate the mounting brackets so hopefully one of them will be close enough in width to fit under my Charger.
I'm guessing I'll need to change the tailshaft as well?

Cool spotters guide.  I have the 8 3/4 with 3:23's and have no problem lighting up the tires and get decent rpm's on the highway.

[charge69]

I think most  people never need more than an 8 3/4 rearend.  My '69hemi auto came with a 3.23 and a suregrip from the factory and will get one (the original one) when it is finished.  They are good for about 800hp and the weight savings is about 100lbs. over the Dana suregrip.

My friend's 11.00 second '69 Roadrunner uses one (the original) and never a problem, even changing out 4 different rear ratios and settling on a 3.55 for now.

[doctor4766]

It actually looks most similar to the 8 3/4" in this pic from another current thread, but I'm sure I've seen a tag saying 8 1/4



Now the housings my friend has are C body and yes we can relocate the mounting brackets so hopefully one of them will be close enough in width to fit under my Charger.
I'm guessing I'll need to change the tailshaft as well?

Cool spotters guide.  I have the 8 3/4 with 3:23's and have no problem lighting up the tires and get decent rpm's on the highway.

What sort of revs are you doing at highway speed with that ratio?
My current setup sits at 2000RPM at 100kmh which is about 62mph. Be interesting to compare.

Love your Charger btw. I've considered chromies myself. They set off the orange nicely.

[c00nhunterjoe]

There is a really cool rpm\tire size display linked on the site, it has a charger instrument panel and you input your tire size and enter your gear ratio of choice then adjust the speedo to see your rpm at any given speed

[doctor4766]

Cool, I'll see if I can find that.

[68RED4SPEED]

http://vexer.com/automotive-tools/speed-rpm-calculator

[doctor4766]

Cheers man

[1969chargerrtse]

It actually looks most similar to the 8 3/4" in this pic from another current thread, but I'm sure I've seen a tag saying 8 1/4

Now the housings my friend has are C body and yes we can relocate the mounting brackets so hopefully one of them will be close enough in width to fit under my Charger.
I'm guessing I'll need to change the tailshaft as well?

Cool spotters guide.  I have the 8 3/4 with 3:23's and have no problem lighting up the tires and get decent rpm's on the highway.

What sort of revs are you doing at highway speed with that ratio?
My current setup sits at 2000RPM at 100kmh which is about 62mph. Be interesting to compare.

Love your Charger btw. I've considered chromies myself. They set off the orange nicely.

Thanks, the wheels came with the car, but sometimes I wish I had the original style with the trim rings. Well?  my factory tach floats a bit so I don't really know? What I do know is I  cruise at 60mph without hearing the engine rev compared to the 4:11's I got with the car.

[doctor4766]

Yeah that's kinda what I'm looking for.
Thanks

[1969chargerrtse]

Here's my 3:23's smokin the tires by just stomping on the gas.
Go to the end of the clip.


http://www.youtube.com/watch?v=_Jba_lYkzRU

Oh and I Love the color of your car, I'd swap colors with you if I could. 

[doctor4766]

Great clip. I'm sure I'll be doing that in no time.
And the colour of my Charger is most likely to be the same as yours. Just looks a little red in some pics

[1969chargerrtse]

Great clip. I'm sur I'll be doing that in no time.
And the colour of my Charger is most likely to be the same as yours. Just looks a little red in some pics

that's for the color change. Amazing. Mine looks orange all the time.
that's for the person leaning on you. Good taste in cars and women.  

[ACUDANUT]

Hey,,,,,,That's my wife....I wish. 

[doctor4766]

Actually she pulled me up on the way to a show a few weeks ago.
Her name's Natalie and she liked my number plate