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boxrodz · 08-29-2006, 02:05 PM

You can achieve a 4-6 drop like 84Custom has or you can go a more popular route like some of the guys have mentioned:

In front, if you plan on retaining your 15" wheel, you may want to go with a 2 1/2" drop spindle. This will avoid any clearance problems between the 15" wheel and the LCA like Slonaker mentioned. Going with a drop spindle also maintains the geometry of the front suspension. Then, add 1 1/2" drop coils. Western Chassis offers both items. When ordering drop spindles, you'll need to know whether or not you have heavy duty brakes by measuring the thickness of the brake rotor. Your brake rotors will measure out at either 1" or 1 1/4" where 1 1/4" is the heavy duty brake system.

In the rear, a flip kit which flips the axle from under the leaf spring to above the lift spring pack would give you a ~5" drop. The flip kit includes brackets that also realigns the pinion angle and maintains the proper drive shaft spacing after the drop. Shock extenders may be included to extend the lowered shock length and retain the some shock angle. Installing the flip kit is relatively simple, aside from having to remove snubber mount (rivets). To drop the rear even lower, using drop shackles like Jeff and 74gmc suggests are common. However, installing the drop shackle may involve notching the rear sill bracket of the bed floor for clearance. To avoid this clearance issue, lowering blocks may be used instead to avoid any clearance issues. Lowering block kits come with the lowering block in various drop ranges (1", 2", ...) and longer U-bolts. DJM offers the flip kip, drop shackles and/or lowering block kits. In the end, you will want to maintain, at least 3" clearance between the axle tube and the frame rail. Otherwise, you may need to notch the frame rail and install a C-notch kit. To determine the axle tube -to- frame rail clearance prior to your drop:

measure the distance between the bottom of the frame rail and the top of the axle tube,

then measure the distance between the bottom of the axle tube and the top of the leaf spring pack,

the difference between the two measurements is the clearance you'll end up with less a 1/4" or so for the thickness of the bracket.

As a alternative, in the front, you can go with a 3" drop spindle instead of the 2 1/2" drop spindle if you intend on running larger wheels (> 15"). Dropped LCAs are also available but should not be used in combination with dropped spindles. You could also run bags, plates and cups instead of a drop spring for ride comfort and adjustability. In the rear, lowered leaf springs, drop hangers/shackles are also available for these trucks. BTW, it is also possible to cut the stock coil spring in front to get the drop of a lowered spring and de-arch the rear spring pack to obtain the drop of lowered leaf springs. With a lowered stance, drop shocks for the front and the rear may be needed.

On a drop of 4/6 (or 5/7), check the backspacing of the wheels you plan on running to avoid any rubbing on the fender wells. Also, expect some LCA damage unless you drive cautiously on rough roads, over speed bumps, entrances, ...

Belltech, DJM and Western Chassis all make lowering components for these trucks. You can visit truckshop.com, stylinconcepts.com, sporttruckdirect.com, performancesuspension.com, macssprings.com to name a few to order the items you need.

Good luck on your build-up (er, down).

08-29-2006, 02:05 PM	#14
boxrodz Until Seventy Times Seven Join Date: Feb 2005 Location: Rocky Mountain Front Range Posts: 1,301	Re: my 75 frame off.. You can achieve a 4-6 drop like 84Custom has or you can go a more popular route like some of the guys have mentioned: In front, if you plan on retaining your 15" wheel, you may want to go with a 2 1/2" drop spindle. This will avoid any clearance problems between the 15" wheel and the LCA like Slonaker mentioned. Going with a drop spindle also maintains the geometry of the front suspension. Then, add 1 1/2" drop coils. Western Chassis offers both items. When ordering drop spindles, you'll need to know whether or not you have heavy duty brakes by measuring the thickness of the brake rotor. Your brake rotors will measure out at either 1" or 1 1/4" where 1 1/4" is the heavy duty brake system. In the rear, a flip kit which flips the axle from under the leaf spring to above the lift spring pack would give you a ~5" drop. The flip kit includes brackets that also realigns the pinion angle and maintains the proper drive shaft spacing after the drop. Shock extenders may be included to extend the lowered shock length and retain the some shock angle. Installing the flip kit is relatively simple, aside from having to remove snubber mount (rivets). To drop the rear even lower, using drop shackles like Jeff and 74gmc suggests are common. However, installing the drop shackle may involve notching the rear sill bracket of the bed floor for clearance. To avoid this clearance issue, lowering blocks may be used instead to avoid any clearance issues. Lowering block kits come with the lowering block in various drop ranges (1", 2", ...) and longer U-bolts. DJM offers the flip kip, drop shackles and/or lowering block kits. In the end, you will want to maintain, at least 3" clearance between the axle tube and the frame rail. Otherwise, you may need to notch the frame rail and install a C-notch kit. To determine the axle tube -to- frame rail clearance prior to your drop: measure the distance between the bottom of the frame rail and the top of the axle tube, then measure the distance between the bottom of the axle tube and the top of the leaf spring pack, the difference between the two measurements is the clearance you'll end up with less a 1/4" or so for the thickness of the bracket. As a alternative, in the front, you can go with a 3" drop spindle instead of the 2 1/2" drop spindle if you intend on running larger wheels (> 15"). Dropped LCAs are also available but should not be used in combination with dropped spindles. You could also run bags, plates and cups instead of a drop spring for ride comfort and adjustability. In the rear, lowered leaf springs, drop hangers/shackles are also available for these trucks. BTW, it is also possible to cut the stock coil spring in front to get the drop of a lowered spring and de-arch the rear spring pack to obtain the drop of lowered leaf springs. With a lowered stance, drop shocks for the front and the rear may be needed. On a drop of 4/6 (or 5/7), check the backspacing of the wheels you plan on running to avoid any rubbing on the fender wells. Also, expect some LCA damage unless you drive cautiously on rough roads, over speed bumps, entrances, ... Belltech, DJM and Western Chassis all make lowering components for these trucks. You can visit truckshop.com, stylinconcepts.com, sporttruckdirect.com, performancesuspension.com, macssprings.com to name a few to order the items you need. Good luck on your build-up (er, down). __________________ boxRODz 1983 C10 SWB Fleetside When two halves is gone, there's nuthin left. Two nothings is nuthin. That's mathematics son. You can argue with me but you can't argue with figures. Two half nothings is a whole nuthin... Last edited by boxrodz; 08-29-2006 at 02:24 PM.