Rookie Rear End Question

[GriffsMonte]

Now that my Monte is soon to be back on the road, and sense i lack a truck and trailer im gonna be driving her to all the shows around the area which for me is a hour ride or more either way i go. 

 

Anyway, I want to get posi on her so i can have some fun. What all do i need to achieve this ?

Also are there any recommended gears for performance and keeping it drivable on the I-95

 

Specs: 350 mild cam and a 3 speed auto trans. stock wheels and rear end right now.

[monte70car]

We had a stock Chevelle with a big block 400trans and 3.31 gears that got 16 miles to a gallon on the high way. My big block Monte with a 700r4 and 2.73 gears gets 13.5 to 14mpg. Are you working with a 12bolt rear end or a 10bolt rear end?

[GriffsMonte]

its looks like a 12 bolt open rear end

[cudax]

its looks like a 12 bolt open rear end

If you are not exactly sure what you have right now, look on the front passenger side of the rear axle housing of the rear end and post the stamped number. That number can be looked up so you know exactly what you have right now, as long as no one else has opened it up and changed anything.

[502ci]

Here's a simple way to tell what rear gears you have...you can do this with the rear still on the car, you just have to jack the back wheels off the ground. If the wheels turn in opposite directions when rotating one of the wheels you have an open rear. if they turn in the same direction then it's a posi of some sort. I think with a posi the wheel only has to go around once to tell the axle ratio unlike the video below.

 

[GriffsMonte]

its an open rear end

[Daryl]

I totally rebuilt my 12 bolt with the following; posi, 4.10 gears, forged axels and disk brakes. Knowing what I do now I would have went with a Ford 8.8 and could have saved about $700. Could be a option for you. I just checked Friday and I'm getting a 8.8 with 3.73s, locker, and disc brakes for 150.00. This would require fab skills though.

[Malyc]

As far as I know, putting in a Posi would just require replacing the open carrier with a posi carrier. As for gears, I'd think something up to like a 3.55 gear would be alright on the street, though since I'm going to be doing my first gear swap coming up here, I couldn't say for sure how much of a difference that would make.

 

Also, this is all based on what I know about my 10 bolt rear, sooooo it may be quite different with a 12 bolt. But, what I know is what I know until I know more

[GriffsMonte]

Thanks for the info guys, i should here back from the shop tomorrow. if all i need i a cam then ill be ordering my parts for the rear by the weekend