What Gear Ratio Do I Need

[bigge31566]

I am restoring a 83 C10 with a 350 approx. 400 hp motor and a 700r4 transmission that's been beefed up and shift kit, I need to do the rear end It will be a weekend driver, It has a 10 bolt 8.5 in. rear in it, what would be the best gear ratio to have with a limited slip posi added, maybe want to spin wheel every now and then but still be driveable

 

[HotRodPC]

Having the OD, and wanting to take strain off the 700r4 since they're farily weak, I'd be thinking 4.10 ish even though it's a 1/2 ton. That'll also help you get that wheel spin that you're lying about when you say every now and then. You know damn good and well if it'll do it, you'll be doing it all the time.

 

[bigge31566]

What about 383s

 

[bucket]

I'd also do a 4:10, especially if it's not a daily highway commuter.

 

[HotRodPC]

Personally, I'd even go 4.10's if it were a highway commuter if I had OD. If I didn't have the OD, I'd probably keep limit it to 3.73 and really would happier with a 3.42 wo OD in a half ton.

And even moreso since it's a 700r4. Take all the strain you can off that 3/4 clutch pack. Keep in mind lower rpm does not ALWAYS mean better mpg. Just need to find that sweet spot rpm range then nail it down at the most often used speed you'd be cruising. So if you have 65mph speed limit and like to drive 5 over, find out what your rpm will be at 70mph and I'd try to be in the 1700-2200 range @ 70mph with my tire size.

With 31in tires 4.10 in OD Locked up 70mph = 2100
With 29 in tires = just over 2200.

31in and 3.73 = 1900
29in and 3.73 = 2000+ (2026)

 

[Driver4r]

Ill be the first to admit that 4.10's In a DD with no OD kinda sucked, but i LOVED the fun of those gears.

 

[HotRodPC]

Ill be the first to admit that 4.10's In a DD with no OD kinda sucked, but I LOVED the fun of those gears.

Imgaine 4.56's with a Th350 non OD and non Lock Up. Thankfully back then the speed limit was 55, but at 60mph and 31in tires, the motor was screaming pretty good. But yep, and a Dana 60 with Limited Slip Diff. I could break the tires loose and get sideways just about anytime I wanted to. It was quite fun. Had 1 buddy that woudln't even ride with me. PUZZY !!! He was skeered !!! He didn't like getting sideways and all that back steering and ****. I loved it. He called the truck, "Any which way but Straight" My daughter called it the "hopping truck". Whe she was 3 and 4yo, I'd put in 1st and stab the throllte off and and she be bouncing on the seat like a basketball when she didn't have her seatbelt on.

My K1500 has 3.73's with No OD, and NO LU. I wish it at least had Lock up, but and OD would be nice since I like to drive it 75mph out to my dads and the motor is screaming pretty good and not getting good mpg. This is why I think this is the truck getting the A833 4 speed OD manual trans.

 

[Driver4r]

Ive seen people running 4.88's on the street with 27" tires.

But with my 4.11's, i was running about 3100 around 65ish. And if i romped on it and kicked down, i could watch my gas guage fall. And my 4.11's have a locker, and yes, i know about sideways. I liked shifting from 1st to 2nd, and the rear end breaking loose and sliding twards the curb then biting and skwaking the tires.

I actually skwaked the tires with the 3.08's the other day, i shifted to 2nd gear at 5500.