Hey guys I was wondering what you guys prefer on gears and tires and what have you done and regretted. My truck is an in town only and doesnt ever really leave town. So I do not know if I should go with 4.11 or 4.56. i'm torn between the two. my truck see's the highway once a month maybe.

302 with gt-40 heads, low rise intake, edie 600cfm,
and SROD tranny with a .70 final O/D

 

What tires? Do you tow? And, when you hit the highway how fast do you drive?

 

31" good year all terrain in front and dakota mt in back also 31.

I do not tow. I'm in college and my trips are short. just to work and to the golf course. and cruise around town. I would like to be able to accelerate quicker with more gear and with so much short driving i do i Thought it might be better to go with the 456 ratio.

I live in bartlesville so when I go to tulsa i usually just drive my girlfriends mustang unless i want my truck so it rarely sees above 60

 

Interesting. I bought Rusty in B'ville and had him towed here to Skiatook.

Anyway, with that tranny you could easily use 4.56 gears since your effective ratio would be 3.19 with the gearing, and the 31" tires would drop it down to 3.09. Thats a good cruising gear for the highway and you could head down 75 to T-town in the truck.

 

I've got a speed calculator spreadsheet made up where you can enter your tire size, rear end ratios, transmission ratios, and RPM to see speed in each gear at selected RPM. Can't get to my share site through the work firewall right now though for a download link.

Here's some examples though:
SROD (3.07, 1.72, 1.00, 0.70), 31" tire

MPH with 4.11 rear, 2000 RPM, 4000 RPM, 6000 RPM
1 - 15, 29, 44
2 - 26, 52, 78
3 - 45, 90, 135
4 - 64, 128, 193
top gear 75mph = 2350 RPM

MPH with 4.56 rear, 2000 RPM, 4000 RPM, 6000 RPM
1 - 13, 26, 40
2 - 24, 47, 71
3 - 41, 81, 122
4 - 58, 116, 174
top gear 75mph = 2600 RPM

 

so I came across a 5.14 tonight that I might buy

 

or is the 5.14 suicide for the truck ?

 

Given your normal use/speeds & tire size, you would be fine. The 5.14 axle would also unload your lighter duty trans a bit more, which is an added bonus.

 

5.14, 2000 RPM, 4000 RPM, 6000 RPM
1 - 11, 23, 34
2 - 20, 41, 61
3 - 35, 70, 105
4 - 50, 100, 149
top gear 75mph = 3030 RPM

 

okay another issue the 5.14 sounds like the ticket but the owner forgot to mention it is a minispool...... mine right now is a limitied slip..... could a shop beable to transfer the limited slip over for a fair price? ive delt with rear ends before and dont really like to work on them because they have to be perfect and i have not done enough of them.

how bad would the spool be. im not to worried about the turning issue but more of the breaking axles.

 

Personally, I wouldn't want a spool for the street. However, a shop may be able to move the ring and pinion to your limited-slip carrier. But, I said "may be" because something I read somewhere said anything above 4.10 doesn't fit on a standard carrier. I'm not sure that is true, but you should check it out before buying it.

 

I've never driven a vehicle with a spool. I did have a friend once who occasionally street-drove his bracket racer Dodge Dart. He said it wasn't too bad except in parking lots it bucked and chirped and was generally annoying.

As far as breaking axles, an empty pickup gets such awful traction that in corners you'll slip a tire pretty easily, way before you stress an axle shaft much. a loaded pickup is a different story though. Put a couple thousand pounds in the bed and you could be in real trouble.

Personally I would never have a spool in a street vehicle, but I don't think it's quite as awful an idea as some say. Still awful , but not necessarily a death sentence for the axles.

As far as swapping your diff into the new rear end, it might be possible (some axles require different carriers for ratios above and below some break point. I'm not sure about yours.

But if you're swapping the diff, why buy the new axle at all? You could buy new gears for your current axle (again with the possible concern about needing a different carrier).

 

so im torn. im just going to have to sleep on it a couple of nights before i choose.

how far off of 75 are you gary?

 

West edge of Skiatook, so about 8 miles west of 75.