how do i lower my truck?

[randyjohn]

i posted this in 73-87 pickups already. wanted to see what this board thinks:

i've been doing a lot of research on this and other websites over the last few months and still and scratching my head as to how i will drop my truck in the back. i'm looking for a 3/4, maybe a 4/6.

it's a 74 gmc 2500. it has the 14 bolt, 10 1/2" ring, 8 lug rearend (3 1/4" OD i think). 9 leaf springs. from pictures i've seen of stock 1/2 ton spring mounts they're the same. there is 7 5/8" clearance between the axle tube and bottom of frame without the bumpstop and 7 3/4" clearance between the top of the diff and bottom of bed so a c-notch would be moot i think.

the front i know they make spindles for because i have 1 1/4 rotors. the back is what's got me stumped. i would actually prefer bags so that i can still haul a heavy load with it (it's going to be my hot rod shops parts runner and maybe have trailer duty). as far as bags go, do i ditch the leafs? take a couple of leaves out and use helper bags?

any insight or ideas are welcome and appreciated.

[Ivan D.]

6" rear drop would be way too much, for a decent ride you need some suspension travel and if you go that low you'll only have like 2" before the differential hits the bed, and that automatically means using real stiff sprngs, which ruins the ride quality right there! I'd suggest that you stick with 2" drop shackles and 2" drop hangers, that will give you total drop of 4" which still leaves over 3.5" travel so it's less likely yer differential will bang up the bed. As far as bags go, because you ain't cutting the frame and the bed I suggest that you run the heavy-duty Firestone "helper" bags, the difference from the standard helpers is those have a higher payload. Mount them on the outside of the frame rails and run individual purge valves, this will eliminate side-to-side sway when cornering while heavily loaded.

[randyjohn]

oh i don't mind cutting the frame or maybe even the bed stringers. the bed floor itself i'd like to keep intact.

[Ivan D.]

I've seen folks put bags on the inside of their C-notched frames, that's why I said it like that. If I were you tho, I'd really keep the bags on the outside, they will hold up much better against body roll. Really the only reason to put bags on the inside would be if you run really really fat tires, if you ain't planning on doing so keep them bags to the outside of the frame.

[SCOTI]

Be aware that ART doesn't recommend 'Air-Over-Leaf' set-ups on some trucks that use shackles & hangers so you'll want to check w/whatever manufacturer you decided on for parts compatability.

With that much room, a flip kit & A-O-L set-up would still allow you to get the truck down & still tow a load.

Or..... check into ART's Air-Bar set-ups (they offer one for 73 up 3500's). If the axle tubes are similar in diameter & size you might be able to use that kit.

[randyjohn]

scoti, when you do an air-over-leaf, how many leafs do you take out? i also found that 1-ton air bar; $1600 and i don't think that includes a tank and comp .

does anyone know if it's possible to raise the bed floor and wheel wells say 2-3 inches?

[SCOTI]

Originally Posted by randyjohn

scoti, when you do an air-over-leaf, how many leafs do you take out? i also found that 1-ton air bar; $1600 and i don't think that includes a tank and comp .

does anyone know if it's possible to raise the bed floor and wheel wells say 2-3 inches?

For a HD-type air-over-leaf set-up, you don't have to remove any leafs if you flip the rear end. That gets you @ least 6" of drop w/no loss in capacity & you have the helper bags to level the truck w/a load (it also won't kill a blue collar budget).

If you opt to leave the rear end below the leafs & remove a few, it will be trial & error to get the height you desire (start w/2 leafs). My feeling is this method will ultimately compromise your total cargo capacity.

The Air Bar stuff is pricy but well designed. I'm not even sure it can be used on 3/4-ton trucks as it's made for duallys but it would be worth inquiring if it's within the budget. It would be easier prob to just swap to a weld-on 4-bar set-up w/some over (or under) the rear axle housing bags.

[randyjohn]

For a HD-type air-over-leaf set-up, you don't have to remove any leafs if you flip the rear end. That gets you @ least 6" of drop w/no loss in capacity & you have the helper bags to level the truck w/a load (it also won't kill a blue collar budget).

If you opt to leave the rear end below the leafs & remove a few, it will be trial & error to get the height you desire (start w/2 leafs). My feeling is this method will ultimately compromise your total cargo capacity.

excellent. thanks for the input.