Hey its my first post on your site, I just bought an awsome 68 SS but am having some issues that some of you may have come accross. First, yes, Im a girl who fell in love with this 68 4 speed 350 CID, and knew that it had a 10 bolt Posi 4:11. I've been driving it around town now about a week an just cant get used to shifting it without having to really gas it in between each gear. On freeway, it runs about 3000rpm at 55mph, and is so loud, and feels like I wish i had a 5th gear but dont. At this point, I really frustrated and dont know if its just my lack of driving experience, or is there something I could do to make it more of an enjoyable ride. In case you have'nt guessed, I have no intentions of racing. PS. go easy on me guys, I'm just learning.

 

There is a 5 speed tranny out there/ It is aftermarket and runs around 3 grand. 3000 rpm at 55 isnt so bad. Its not so good, but its not so bad. Whan is the last time the engine was tuned up? Maybe thats all it needs.

 

On the other hand if you are not planning on racing it or running it too hard a new set of differential gears may work better for you. 4:11 gears are fast to take off, and as you've noticed not much for freeway driving. I am rebuilding my rear end with a set of 3:42 gears in it, and yes I am going with the 5 speed tranny with .68 OverDrive.
You can google a RPM calculator and get a easy program that will allow you to input tranny, gear ratio, tire size, then enter your desired speed and it will pop out the engine RPM. Fun to play with at least.

 

Since you don't plan on racing the car, you should change the rear end gear. A 3:23, 3:31, or 3:42 would be ideal for street driving. That will get the R.P.M lower for cruising, which not only will be quieter, you will get better gas economy. Like member SS396, I also have a set of 3:42 Richmond gears in my '68 SS and it does about 2500 rpm at 60 mph. I actually have 2 - 1968 SS convert's and the other one has a 3:73 rear end and it rev's around 3000 rpm at 60 mph. Both '68s have 255-60R15 tires.My '69 SS396 has a 3:08 gearwith 14 in. tires and rev's around 2300 rpm at 60 mph.You will need to calculate your tire size to your rear gear and also change the speedometer drive gear inside the transmission in order for your speedo to read correctly... regards George

this website will help you determine what you need...

http://www.v8volvo.se/mekartips/arti...eedo-gear.html

 

Good advice George. I had a '69 Z/28 with 3.73 gears that ran around 3,000 RPM @ 60mph, ran pretty well but gas mileage was only 12-14 highway, my good friend had a 396/325 with I believe 2.73 gears that ran a little under 2,000 RPM @ 60mph and much better gas mileage.
Clyde

 

Welcome to the forum
Your not the only girl, there are a couple on here
Like what the others have said, a rear end gear change would be the best way to go. I would find out what gears the factory choices where for the SS so you can keep it factory correct. If you do change the trans, keep every thing so you can put it back to org.
Also you prob. have Flowmaster Mufflers on it if its that loud, You can have some Super Turbo mufflers put on , and it will make it quite
Its nice to see more women on here and into cars.
Where are you from?
We also like to see pics

 

got..........pics?

 

Somewhere in this forum I posted recently with the rear gears available for '67-'69, don't remember which thread, but it was in the last couple of weeks.
Clyde

Edit: found it. Positraction rear ratios 1967: 2.73, 3.07, 3.31, 3.55, 3.73, 4.10, 4.56, 4.88. 1968: same as 1967 except add 2.56, add 3.37. 1969: same as 1968 except add 3.36, delete 3.37.

 

What other plans do you have for the car?

 

Haha...Pics of the car that is...