ford 9" vs 8.5" 10 bolt

I know of a basically stock Ford 9" for sale that came out of a Versaille (58.5" with factory disc brakes) with 3.90 gears, stock 28 spline axle and an open diff. At a minimum it would require a posi and probably 31 spline axles. Total investment including the rear would be about $1100.

I currently have a 8.5" 10 bolt with strange 28 spline axles, fresh 3.73 gears and bearings and c clip eliminator. The car is a big block 56 chevy 5 speed car with slicks, 12 rims and ladder bars that is primarily street driven but goes to the track 3-4 times a year.

I have heard everything from 10 bolts stink and wont hold up to there are cars running 9 and 10's with them. Im not made of money so I am asking you guys what you think. Is the 10 bolt worth working with or should I **** it up now and convert to the 9"?

 

If it aint broke yet why fix it? I've run an 8.5 in my BBC powered cpe for 64,000 mi without trouble yet. I'm not running slicks but I don't baby it either.

 

I've been running a 10 bolt in my 38 Chev for about 20 years, 3:08, behind a Turbo 400 and a 461 Olds with about 500 lbs. of torque. At the track I do over 200 runs a year, maybe 300. 1.72 60 ft times and 12.8's. BFG Drag Radials.Never has it break. It is stock...Frank Kunkel (nostalgia Drags DVD man) Almost 100,000 miles, drive to track.

 

I have an 8.5 inch 10 bolt 4.88 gear posi in my 55. No problems.

The guy that had the rear before me had it in a crude late 60's Nova that was jacked way up in the air with a set of 15x14 drag slicks on the back and the car was drag race only with a radical big block in it. He was punishing the rear but never broke it.

Yeah, a 12 bolt or 9 inch would be better and maybe have better bragging rights, but I don't think you will have a problem with what you have.

Of course, there is always that fake 12 bolt cover available on ebay...

 

save your bucks, 10 bolt will be fine

 

The factory disc brakes **** ... and are very difficult to find parts for and expensive IF you do. ALL of them were 28 spline so NO factory 31 spline axle upgrades ( all aftermarket required ).

Run the rear end you have until it breaks ... THEN go to a 9 inch ... 57 to 59 Ford rears are 2 inches more narrow than a stock 56 rear.

OR ... You can buy factory longer Ford rear axle housing with 31 splines ... use the 'SHORT' 31 spline axle as the long side ... after you narrow housing and then narrow and respline the long 31 spline axle ... for not a lot of money.

 

Lots of people running the 8.5 in Stock Eliminator and getting by with no troubles. I think you will be happy with it.

 

I think the 10 bolt rears got a bad rap from the older pre 8.5" units. The 8.5" rear replaced the 12 bolts in some cars after 1970. I run 9.90's on a beefed up 8.5 and have a buddy that runs 8.30's with no trouble for years.
It should hold up fine .
Doug

 

keep the 10 bolt my nova has one and i pound the **** out of it and it hasnt broke yet....

 

Little known fact: 9" Ford rears **** up a few more horsepower than Chevy 10 or 12 bolt. It is because of the extra friction/drag of the increased pinion to ring gear mesh of the 9" design.