72 Gmc k15 Lift adivice

[72 k15]

Gonna need a small lift on my 72 k15 danna 44 front 12 bolt rear going to convert to a 4spd, putting 33s on will the 3.07 and the granny low gear be enough to take off with 33s?, Looking for a small 2-2.5" lift to fit the tires and get some ground Clearance will be driven as a daily so hoping for a good ride.

[sweetk30]

i had 4.10 gears and 4 speed . never used 1st much with even 35" tires . but jumped up to 38" tires and had to start more in 1st gear .

so short answer you prob wont notice much . .

look at tuff country suspension lifts for a good off the shelf ride .

ruff country ride just like there name . i wont even deal with them .

these people are SUPER quality service . http://www.offroaddesign.com/catalog.htm

and as to shocks lots of guys are going bilsten shocks for the best leaf spring ride and shock combo .

[72 k15]

Thinking ill go with the tuff country 2" should clear 33s, I am going to need to do some highway driving to get the play spots so I am wondering is 3.07 gears will work with 33s would I have to use the granny to get going?

[Mike C]

The real issue is fuel economy on the highway. My experience with big tires and no gear was crappy mileage because you were below the efficient operating range of the carbureted motor setup. I would start saving for a gear swap. 3.73 with 33" tires or 4.10 with 35's. My 4.10's are the perfect gear for the 35" BFG AT's on my truck.

[72 k15]

Originally Posted by Mike C

The real issue is fuel economy on the highway. My experience with big tires and no gear was crappy mileage because you were below the efficient operating range of the carbureted motor setup. I would start saving for a gear swap. 3.73 with 33" tires or 4.10 with 35's. My 4.10's are the perfect gear for the 35" BFG AT's on my truck.

The problem with upgearing is,rpm ill be at 3000rpm at that point on the highway and need to swap in a nv4500 (2000$) at least plus gearing... Will be putting in a TBI unit as ND is cold as hell my 02 sierra 5.3 starts in -40 easy unplugged.

[special-K]

My '90 Blazer had 4spd, 3.08s, and 33/12.50s for most of it's life. It did fine. Yeah, it was a lunge starting off in 2nd, but that thing rolled on out. Never missed O/D in that thing. On a real steep take-off I'd use 1st. With 3.08s it wasn't ridiculously slow. It yanked right out, but the shift came quick.

[sweetk30]

70 mph with 33.0 tall tire

3.08 = 2200
3.42 = 2440
3.73 = 2660
4.10 = 2920

[72 k15]

Originally Posted by sweetk30

70 mph with 33.0 tall tire

3.08 = 2200
3.42 = 2440
3.73 = 2660
4.10 = 2920

Speed limit here is 75 the flow is about 80-85 I think im going to 3.73s and swap in a nv4500 anyone here done that?

[sweetk30]

that be a good combo .

lots and lots of nv4500 swaps out there done .

nv4500 swap with 33.0 tire @ 75mph

3.08 = 2350 4th / 1760 5th o/d
3.42 = 2610 4th / 1960 5th o/d
3.73 = 2850 4th / 2130 5th o/d
4.10 = 3130 4th / 2350 5th o/d

here ya go play more if you want . every box can be changed for speed / feet / mph distance . huge drop down window for trans options . http://www.grimmjeeper.com/gears.html

[72 k15]

Originally Posted by sweetk30

that be a good combo .

lots and lots of nv4500 swaps out there done .

nv4500 swap with 33.0 tire @ 75mph

3.08 = 2350 4th / 1760 5th o/d
3.42 = 2610 4th / 1960 5th o/d
3.73 = 2850 4th / 2130 5th o/d
4.10 = 3130 4th / 2350 5th o/d

here ya go play more if you want . every box can be changed for speed / feet / mph distance . huge drop down window for trans options . http://www.grimmjeeper.com/gears.html

Would it be worth it going with 4.10s or just keep 3.73s with that overdrive,cool website haven't found one that useful in a while. Have a thread on a nv4500 swap?

[sweetk30]

the way i would do it is put your cruising rpm in the middle of the power band of the engine so your not working it hard .

and check to see what the carrier split is for each axle so you can price out gear swap parts . you might need new carriers for the jump to 4.10 gear .

most of the time its cheeper to go used axles with the gear you want than install all new in both unless you can setup gears your self .

[Mike C]

I know you can get thick gears for the 12 bolt so no need to change carrier. I have not seen those for a Dana, but a stripped open carrier for 3.90 and up gears in the 44 shouldn't be more than $100.

Another thing you can do is look for a 3/4 ton 4x4 Suburban donor. I have bought a couple and swapped the better geared 8 lug axles into not only my Jimmy but my kids project truck as well. The '86 had 4.10 gears that I swapped into my truck keeping my Dana 44 front but using the outers from the 10 bolt since I already had 4.10 in it.

On my kids, the '84 donor had 3.73 and we did swap in the 10 bolt front since his truck had 3.07 as well. I paid $300 for one of them and $200 for the other. Although I haven't had much luck finding cheap donors recently.

[72 k15]

Originally Posted by Mike C

I know you can get thick gears for the 12 bolt so no need to change carrier. I have not seen those for a Dana, but a stripped open carrier for 3.90 and up gears in the 44 shouldn't be more than $100.

Another thing you can do is look for a 3/4 ton 4x4 Suburban donor. I have bought a couple and swapped the better geared 8 lug axles into not only my Jimmy but my kids project truck as well. The '86 had 4.10 gears that I swapped into my truck keeping my Dana 44 front but using the outers from the 10 bolt since I already had 4.10 in it.

On my kids, the '84 donor had 3.73 and we did swap in the 10 bolt front since his truck had 3.07 as well. I paid $300 for one of them and $200 for the other. Although I haven't had much luck finding cheap donors recently.

Ill most likely just re gear the axles to 3.73 to keep it stock rear has a stock post should I go locket or post front? any good brands yukon?

[72 k15]

Anyone know how to do the nv4500 swap?