I have a 89 formula with l98 and 327 gears want to upgrade to 342 but not sure what to get for a direct fit thanks
also what should i xexpect to pay for installation of the gears thanks

 

Did your car come with the Posi. option ? If not now would be the time for the up-grade.

 

yes it came with it just not sure what gear set will fit

 

There are a couple of crude methods of determining your rear gear ratio. The first is to drive on the freeway at a certain MPH (You have to be sure your speedometer is accurate for this one) and record what RPM the engine is turning at. You then plug these values into the final drive ratio calculator on TGO in the tech section along with your tire height and it will give your theoretical gear ratio.

The second way is to jack the car up, and turn the rear wheels one full rotation while counting the number of times the driveshaft turns IE 3 and one quarter turns of the driveshaft probably means 3.23 gears.

The surefire, foolproof way however is to pull the diff cover and check the markings stamped into the ring gear. Pulling the cover off is not difficult at all with a jack and some patience. When I did I had 28" tall tires installed so I was able to just crawl right underneath the car with it sitting parked and change my rearend fluid. BTW, if you have no clue when the last time the diff fluid was changed this would be a perfect excuse to do so.

 

ok thanks my rpo code says he rearend is 327 and i want to upgrade to 342 just not sure what to buy

 

Richmond, GM and Moser are 3 great companies to buy gears from. I have heard that the richmond gears are made primarily for racing and have a tendency to howl at speed due to the straight cut teeth.

 

great thanks for the help

 

If you have 3.27 gears, that means you have a Borg Warner 9 bolt. The only gears for that axle are 2.77,3.08,3.27,3.45 and 3.70 and they are hard to find. If the engine is going to stay stock or near stock don't change the gears.

 

thats good do know how do you find this kind of information out and were would i look

 

All around this website and google my friend. I've been dabbling around with cars for the past 3.5 years. Alot to learn. Scary at first, but once you learn this, learn that and then start to figure out how this affects that it will all come together.

Just one thing is you have to learn to take what some people say especially on forums with a grain of salt. Alot of people "think" they know what they are talking about, but are just regurgitating what someone else told them without investigating the why behind the how. General rule of thumb for me is if I see something posted on a forum, unless it has a highly credible amount of factual information explaining it or comes from a highly credible member, I always do my research on the subject before I accept it as fact.