Hi guys im sorry if this question has been asked 100 times before!!

Im about to put my car up for the winter and would like to get my rear gears and carrier changed to 3.73 posi.

my car is a 1971 delta 88 stock 10 bolt diff cover.....3.08 one tire fire right now...which I think stock axil are 28 spline.....so if all my info is correct what should I order??

I don't intend on doing this myself so my question also is should I just order the parts myself from napa or just remove the diff from the car and just bring it to a shop and get them to do it all!!

 

If your going to let someone else do it, then I'd let them do the whole job. Ask the shop which they prefer as far as to leave it in the car or not.

 

Chances are, they want the rear end out of the car instead of crawling under it...haha Yes, bring the entire rear end to the shop and ask, don't be afraid to shop around and ask auto shops that have been in business for 20 something years and see where they go. The guy I used to go to is now is over 70 years old and has always worked out of his garage.

 

I would make sure you want that low of a gear . I have 3.90s in my Rallye and i will say i dont like running over 60 mph for any milage sure it will zing but just seams like it is working way to hard for to long . I would say and maybe you have but get with a car that has that low of a gear set up with a 3 spd and see what you think for how you are going to use it. My brother Did the same thing with a grand lemans put a four speed and low gears not he is kicking himself he is 20 miles form anywhere . BY the way I REALLY LIKE THAT DELTA!

 

Find out what ratios are available for that rear. Contact Fabcraft,and see what they have.They can supply a whole kit.I think they make a 3:55 for that car.You can also contact Monzaz.He might have a complete rear,already built.

Yes,I would rather work over it than under it.

 

That car sounds good, what cam are you running? 3:73 won't be fun on the hiway. I have 3:55 gears and don't like them much on the hiway either!

 

I'm running 4.10's in my 67. Brian Trick did the diff in my car. I was skeptical, but took his advice. I have a 700r4 with 4'th as a 0.70 OD. Once got the governor calibrated, I totally love it. Runs in the powerband around town, and 65 mph is about 2400 rpm. If you have a 1.0 final gear I agree, I used 3.23 in my last three speed auto machine.

Tim

 

My 1971 Royale was a 2V(2-barrel) 455 engine from the factory. The rear-end is a 2:73 open 10 bolt cover. I believe these are a corporate GM 8.5 rear end. I also have a 1971 Olds 98 (455 4V) has a 12 bolt cover 9 3/8 posi. I also have another 1971 12 bolt cover 9 3/8 3:23 posi that I took a pic of the cover (not very good, I wasn't about to move it for a better pic.) Your cover (10 bolt) will have the "hump" like the A body 8.5. If yours is the 8.5 you have more ratio's to chose. I wouldn't go over 3:42 for on the street with a turbo 400. I guessing your car was a 2 barrel 455. Are you sure it is a 3:08? JMO, Ken