T56 behind a 461 Pontiac in a 71 Lemans

[pontiacpower]

Well as far as tires go..... mine are probably 28 inches tall not sure how wide.but they are street tires so I don’t I could destroy a rear end that lived behind a lot of drag cars over the years

[pontiacpower]

Well as far as tires go..... mine are probably 28 inches tall not sure how wide.but they are street tires so I don’t I could destroy a rear end that lived behind a lot of drag cars over the years

[silver_bullet]

It all depends on the condition it is in now, and how hard you shock load it once you start driving it with the new combination... remember that the axle housings are pressed into the pumpkin...I have seen them slip and twist on a hard launch, some people weld those joints to prevent this from occurring... also as mentioned before. sticky tires would not be your friend in this application...

[pontiacpower]

Copy that. I just hope this 10 bolt will hold up in a straight line you know.

[silver_bullet]

I run through ads for Pontiac stuff daily and I’m more and more tempted every day. I’ll give the guy a call. But when you “freshen” a rear end what does that mean? Change fluid and gasket? In the ad he said both wheels spin together but it could use a freshen up

In most cases, I would consider freshening up to include the following: visual inspection, new axle bearings and seals, check gear lash, gasket and fluid (don't forget the posi additive if so equipped/required). Make sure to look for signs of axle and housing twist.

[pontiacpower]

I run through ads for Pontiac stuff daily and I’m more and more tempted every day. I’ll give the guy a call. But when you “freshen” a rear end what does that mean? Change fluid and gasket? In the ad he said both wheels spin together but it could use a freshen up

[AndyB]

^ Super true.

If you run smallish tires, you'll have a very hard time getting enough shock load to break the differential. Not to say that it isn't possible, as ten minutes with a 17 year old driver could demonstrate, but it's much more difficult.

[Dan Barlow]

If it’s thumpinn455 (Todd I think)

Yep . My job here is though .
For $100 I'd put that 10 bolt posi in there and then save for a new 9 inch as per Loren . Then again , I ran a 9 bolt Aussy in my and my oldest sons 3rd gen F bodies and never had any problems . Just stay away from slicks VHT and drag strips . Sometimes lack of traction can be your friend . We were running 255.50.17s

[Loren]

It's not easy being me.

[SuperBuickGuy]

Different than Chevy then, where the '68 Chevelle is where they got wide. See whatcha get from a Chevy/Ford/Mopar guy?

if you weren't so divided in your loyalty ....

[pontiacpower]

Sounding like 9 inch might be the way to go after all..... I do remember pulling the gears that change the ratio and I knew nothing about rear ends(still know nothing about rear ends) and it took me less than 20 minutes to get them out with an old timer telling me how to do it.

[Loren]

but the 67 rear isn't the narrow one... 64/65 only.

Different than Chevy then, where the '68 Chevelle is where they got wide. See whatcha get from a Chevy/Ford/Mopar guy?

[pontiacpower]

Sbg what can you say about them bop 10 bolts. I’ll be 600 hp/tq at the crank for sure but I won’t be doing crazy stuff like autocross. What’s it take to make one of these things run that kind of power

[SuperBuickGuy]

You've mentioned lots of HP someday, I think you'd maybe want to end up with Ford 9" then eventually... Nothing bolts in but you can buy them modified to do so such as:

[URL]

But for now, $100 to get a narrow-style axle with your present brakes and driveshaft possibly being a direct swap, that would get your tires out of your fenders, be cheap, and get you on the road then just beat it up 'til it breaks...if it does. Maybe you take it easy and it lasts forever? In any event, SBG who is already here can tell you more about B-O-P rears than any of of the rest of us Chevy-Ford-Mopar people.

but the 67 rear isn't the narrow one... 64/65 only.

while I may bemoan the non-use of the BOP rear, I'd never spend the money on one - too many limitations - if anything I'd put a 12 bolt for period correct and a 9" or 8.8 for best strength/value.... and for the record, I learned about BOP rears with my 70 Skylark and replaced it with a 12 bolt.....

[Loren]

You've mentioned lots of HP someday, I think you'd maybe want to end up with Ford 9" then eventually... Nothing bolts in but you can buy them modified to do so such as:

https://www.speedwaymotors.com/Speedway-Ford-9-Inch-Bolt-In-Rear-End-Axle-for-1964-67-GM-A-Body,291301.html?sku=99006466&utm_medium=CSEGoogle&utm_source=CSE&utm_campaign=CSEGOOGLE&gclid=EAIaIQobChMI6tK8speb4QIVSrXACh1U0wmpEAQYAiABEgJHC_D_BwE

When that time comes, for $950 I wouldn't bother trying to make up one myself. Cutting to width, getting or making and then welding on the right brackets in the right place, spec'ing and buying axles, unless you want to get into the fabrication or rear-end business that's a lot of work when you can get something out of a catalog for 1K. Then of-course you buy or setup a center section with the gears and traction, another $500 to $1,000. Best be sure of what you're doing by then, knowing exactly what gears you want etc.

If you were ready to drop 2K on a the best rear right now and (again) were positive of the gears you want, I'd not waste any effort and go straight to that.

------

But for now, $100 to get a narrow-style axle with your present brakes and driveshaft possibly being a direct swap, that would get your tires out of your fenders, be cheap, and get you on the road then just beat it up 'til it breaks...if it does. Maybe you take it easy and it lasts forever? In any event, SBG who is already here can tell you more about B-O-P rears than any of of the rest of us Chevy-Ford-Mopar people.