Decide which lift kit you want, then contact the manufacturer. A 6" lift may not be enough for your plans of 37" tires. I have a 6" lift with 35" tires. You should consider a 12" lift.

• Bulletproof Kit $3,590.00
• Atlas leaf springs $1,090.00
• Bulletproof 2.0 Reservoir shocks (Set of 2) $570.00
• Bulletproof 2.5 Coil Overs/Springs (Set of 2) $1,590.00
• NEW Front Coilover Reservoir Mounting Brackets ($25X2) $50.00
• Bulletproof Billet Shock Clamps ($30X4) $120.00
• Rear Traction Bars $760.00

Total: $7,770.00

• 4WD will require CV Front driveshaft $690.00

Shipping and any Taxes that may apply are not included in above prices. Tire Size: 38”-40” & Required wheel backspacing 4 ½”

 

I use this handy tool all the time, along with a tape measure...

https://tiresize.com/calculator/

 

I don't think he will get 37" tires to work with any OEM suspension.

 

Sure would be nice if he would tell us what kind of truck he has...............