8.5 10 bolt in the mid-low ten's looking for ideas

[chazmat2316]

It's time to update the stock rear in my GN,and I'm looking for ideas,see what other people did,or think? It's just a street car with DR's,no trans brake I drive on the street alot,this car is fun,and I want to keep it that way! I already have a race car,and don't want this to be another! I have a 70 bb turbo & all the go fast stuff,now it's time to do the rear & drive shaft. I was thinking of 30 spline axles,and posi with ford ends,or do I just spend the bucks for a 12 bolt? A Dana 60 sounds overkill,and can't get lower than 354 gears with might be too much gear. What have other people done in the mid-low 10's zone? I'm also looking to put in a 6pt bar to keep the car together,I know the NHRA will want more but TOO BAD! like I said it's a street car! I'll make a few passes till I get kicked out & go home. I raced my other car deep in the 9's for a long time without a comp lic. Thanx for any input,and thoughts! Have a great new year Charlie

 

[Raymond Bunch]

There have been many stock 8.5's that have gone deep into the 10's with just an after market sway bar, air bags and LCA. I believe there are even a couple in the 9's if my memory serves me correct but it's pushing it without upgrading the axles. If it's just a street car, I wouldn't even bother to be honest with you. I'm sure other will chime in......

 

[Louie L.]

For what you described, upgrading the 8.5 is the way to go. How big you go on the axles dpends on what center section you want t run and their availabilty in that spine count. You said you dont want a race car , so a Posi-locking type diff should be used. Most are only available in 30 spline last I checked.

Good Luck

 

[chazmat2316]

28 spline is kinda weak!

do ya think 30 spline will live? can you buy a posi for a 8.5 in 33 spline?

 

[pacecarta]

cottons great pumkin has been 8.90 with an 8.5

i beleive Jack is running similar to what i run in my 86 which has been low 10s off T brake ,
33 spline mosers , moser clip elims , moser spool, good studs

as for the bar and NHRA tech , all you need is a 6 point for our cars and you dont even need the passengerside door bar so only 5 points are nescessary for tech to 10.0 and speed under 135 , and must be welded to the frame

and stock axles have no place on the track with a modified buick 6, read the NHRA rule book

once you hit 9.99 or faster than 135 it all changes

 

[strikeeagle]

60 foots?
Transbrake?
Launch Boost?
Launch RPM?

These are all better indicators than ET so far as how stout a rear end needs to be.

If and when I get the rear end in my T built I'll go right to Mark Jackson for their advice because they make the best stuff in the business, bar none, and I won't care if it costs a little more because it's incremental and cheap insurance.

I know that MW does not advocate candyazz 28 and 30 spline axles for anything serious. More like 35.

www.markwilliams.com

strike

 

[alec296]

i suggest getting the TA girdle/cover along with big bearing axle change
weld axle tubes in also.
i have same setup with a spool in my big block car. i know the 8.5 can
hold up to a bit of punishment but like anything ,it has its limits.
if anything you will be ready for the next upgrade you do to engine.
andy

 

[chazmat2316]

Yes I know stock c-clips no good! can I buy a posi over 30 spline? will 30 spline hold up? I do have good adj control arms,& 1.5 bmr sway bar. Thanx

 

[chazmat2316]

Is a 6pt bar go for 10 flat? I thought it was 10.99

 

[pacecarta]

10.00 , under 135

 

[chazmat2316]

10.00 very good to know thanx! What do TSM guys do for Rears?

 

[49-blues]

Anyone have any personal experience with the detroit true- trac rear spool?

 

[c&cgn]

I have an Eaton 30 spline posi and Moser axles, with Ford ends.

Also went with TA perf rear-end gridle and brand new GM ring and pinion just to be safe.

I did a post at the time I was upgrading ( a couple years ago now) and there were quite a few guys running upper 10's with just Moser 28 spline replacement axles. I would go 30 splines just for the extra safety factor for low 10's.

Any of the big name suppliers will tell you you need at least 33 spline axles and a spool etc. That's what they told me at the time.

My car 60's in the 1.4's off the foot brake with no issues since the upgrade.

 

[chazmat2316]

Thanx to all for their input! I also spoke to Cotton who set me straight! I'm goin 30 spline axles & eaton posi. It's a dam street car anyway! Don't think it will 60 ft faster than a high 1.40 anyway! Yeah everyone I called wanted to sell me 33 spline or better in a 9inch or Dana! While my race car has a 12 bolt with 33 spline with 17-33 tires that 60's in the mid 120's on the rear tires! The buick is just a street strip car,with is about 99% street! This things more fun than the race car anyway,can drive it anywhere,and play around on the street! What do most TSM guys do about a rear, and what do they 60 ? Everyone have a great new year. Charlie