question about 4.56 gears and my truck

[xgruntusmc]

hey guys, i need your help.  i've got a stock 12 bolt rear and 10 bolt front end on my 78 chevy K10, i'm looking to get rid of the stock gears and move up to 4.56 gears to one, give me some low end, and two, prep the truck for when i lift it and throw larger tires on it.  anyone know right off hand what size gear (inch wise) i'm looking at in that rear and front end without taking it apart? i'm open to any and all feedback.  thanks again

[Engineer]

12-bolt should be 8-7/8".

10-bolt should be 8-1/2".

Are you sure your '78 has a 10-bolt? All of the '78s I have seen have the Dana44.

[dvdswan]

a thing to remember when going that low of gear, you will have to buy a new carrier as well.  I think the carrier break is either 3.73 or 4.11 for both axles.  my 78 has a dana 44.

[bake74]

a thing to remember when going that low of gear, you will have to buy a new carrier as well.  I think the carrier break is either 3.73 or 4.11 for both axles.  my 78 has a dana 44.

     Your hy-way speed will suck if you plan on driving anywhere.

[xgruntusmc]

thanks for the input, i really don't plan to go too fast, but i may consider 4.11's because i know there will be times where i'll be doing more than 40.  and i also have the dana 44 10 bolt front and it has a 12 bolt rear.  I honestly wish i had a better understanding and knowledge of gears but unfortunately i do not.  My goal with this is to take and transfer it's power to the low end and be able to get out of it's own way, then eventually lift it and throw some 37's on it.  it's just a hunting, camping, toy truck anyway so it won't be driven that much

[zieg85]

I have 4.56 in my 1 ton.  HATE it...  Beyond 55 that motor is screaming and I have pretty tall tires on it.

[hatzie]

With those gears you really need overdrive.  I have the same gears in my M1008.  The 4L80E tamed them fairly well.

From orbit on my Android.

[Irish_Alley]

heres another issue you might face. you are only running 1/2 ton axles. tires to compensate the ratio (+40") will beak your axles up in no time. save some time and money go to the junk yard and get a 1 ton or ¾ ton running gears and be done you will get at least 4.10

[bake74]

I have 4.56 in my 1 ton.  HATE it...  Beyond 55 that motor is screaming and I have pretty tall tires on it.

     I ran 5.56:1 in a jeep Dana 44 axle for years, the top speed on the freeway was 60 MPH if I was lucky, that is why it got trailered to every trail.   

[Dan75k20]

My buddy has a 77 k 5 0n 40s  sm465 5.13s and a Dana 44 and 14 bolt built 383 breaks stubshafts every once in a,while needless to say he is installing a d60 save for the 3/4 tons or 1 tons before you spend,the money for a 10 and 12 bolt