zerorate/wheelbase question and 73 build-up pics

[chevyin]

Hey guys, been working on the 73 lately. When I bought it, it had a 4" lift and 33's. Im now changing to 8" (skyjacker) springs with zerorates with 39.5 TSL's. First, a few pics:

Before, as purchased basically:

And its current condition:

Okay... now the question. As you can tell from the pics, Im doing more than just the suspension change, also entire new drivetrain. New front and rear driveshafts. So before I order the driveshafts Id like to figure out my final wheelbase. When I add the zerorates (truck just has the 8" springs installed right now, in the pics) should I extend the wheelbase, or leave it stock? If change it, just front, just rear, or both? Go 1" or 1.5"? Ive researched it and only seem to see people talking about changing their wheelbase just for the sake of wanting a longer base. My main concern is tire clearance. The pics show I have a decent amount now, and adding the zerorates will give me another inch. But I dont want to trim the fenders.

I realize with 8" springs this thing isn't gonna have alot of flex, maybe this isn't even a big issue, I don't know. Basically, what do you guys think? Id like to figure out what to set the zerorates at (offest or centered) so I can start thinking about ordering the driveshafts (HAD).

Any advice on why I should change the wheelbase or leave it alone would be appreciated. TIA guys.

 

[ryan22re]

my guess is with 8 inches, the driveshafts will be too short anyway.

looks like you are running crossover so i think id try and move the front axle 1.5 inches forward for tire clearance. maybe buy some d60 spring plates from kert too. that way you wont have to mess with grinding the original d60 plates.

 

[chevyin]

my guess is with 8 inches, the driveshafts will be too short anyway.

looks like you are running crossover so i think id try and move the front axle 1.5 inches forward for tire clearance. maybe buy some d60 spring plates from kert too. that way you wont have to mess with grinding the original d60 plates.

Thanks for the reply. Yes, the original driveshafts will be too short. Figuring on new ones from HAD, just want to nail down the wheelbase before I order them.

I should have mentioned, I have an ORD xover steering kit for it (plus hydro-assist), usual steering/frame braces, ORD d60 plates etc. I think I pretty much have everything I need, just need to decide what spacing is best for the tire clearance. Is moving the front 1.5" forward the best for fender clearance then? I guess I always assumed GM mounted the wheels centered, but I also know Im changing alot with all these mods. Again, thanks for the reply.

Keep em coming.

 

[nstarry]

front foward 1.5'' ! I am doing the 52'' swap to help go foward 2'' . last summer I stuff the tires in to the wheel wells and that was the only thing that would rub was the inner fender well at the back . 2'' foward and I think I can put all the way in ! ( 38s 6'' lift )on 74 k5 . I dont know if this helps I dont know what your planning on doing (rocking , mudding...) but thats why I went foward

 

[chevyin]

front foward 1.5'' ! I am doing the 52'' swap to help go foward 2'' . last summer I stuff the tires in to the wheel wells and that was the only thing that would rub was the inner fender well at the back . 2'' foward and I think I can put all the way in ! ( 38s 6'' lift )on 74 k5 . I dont know if this helps I dont know what your planning on doing (rocking , mudding...) but thats why I went foward

Front sorward 1.5"... got it. I suspected as much. None in the rear tho (centered)?

As for the truck's uses, between me my brother and father, there's a few K5's around here including relatively stock ones and one that will be a rock climber. But this truck's purpose is more all-around. I have alot of varying terrain here where I live, including sand dunes, mud and mountains, so I hope it will do pretty well in all areas. Like I said before, I know with 8" springs its not gonna be a serious rock crawler, but hopefully it'll do most things well. Thanks for the input.

 

[chevyin]

A few more specs on the truck are:

396 bigblock
massaged turbo400 HD
Atlas II 3.8 w/ HD front output shaft upgrade & 1350's
Rear 14bff disc'd & detroit'd
Front d60 w/ ORD spring plates (ARB eventually)
ORD xover steering (maybe high-steer eventually)
WestTexasOffRoad hydro-assist steering
8" skyJacker springs + zerorates
USA6x6 double beadlocks w/ 39.5" TSL's (not the wheels shown in the pics)
High Angle Driveline driveshafts

 

[Leper]

With that size tire, move at least 1.5 forward. If you have to trim, you can just cut a straight line on the bottom of the fender in the front.

 

[chevyin]

With that size tire, move at least 1.5 forward. If you have to trim, you can just cut a straight line on the bottom of the fender in the front.

Okay so another vote for 1.5" forward in the front. So again, centered rear then?

The front fenders have already been trimmed slightly, probably the cut you are describing. Thanks for the input Leper.

 

[Leper]

I would leave the rear centered. I run 56" springs and left it centered. If I hadn't done the cage already, I would have moved the axle back. I have wheeled it with the current setup and I am happy with it.
With the 39.5 tires, if you have a flexy suspension, you may need to take the corners out on the rear opening. I trimmed a bunch, but I am only running a 5" lift with mine.
pic
http://www.dallask5.com/images/100_0571.JPG

 

[Greg72]

Okay so another vote for 1.5" forward in the front. So again, centered rear then?

The front fenders have already been trimmed slightly, probably the cut you are describing. Thanks for the input Leper.

Are you planning to run crossover steering? Moving the front axle forward is going to make a short (stock) draglink even shorter. You're really going to be hating life with a steering setup like that....unless you're willing to relocate the steering box forward as well????

Out back, I'd just make sure that the wheel/tire looks "visually" centered in the wheelwell once the lift is complete and you have the final weight on the springs....maybe drop a plumbline from the center of the opening and compare it to the hub center.

 

[Leper]

I have an ORD xover steering kit for it (plus hydro-assist), usual steering/frame braces, ORD d60 plates etc. I think I pretty much have everything I need, just need to decide what spacing is best for the tire clearance.

Yes.

 

[Greg72]

Yes.

Ooops!

There may still be some clearance issues with the steering (pitman arm , etc) but the crossover is definitely a good idea when the axle starts creeping forward.

 

[RaisedK5]

The rear springs will move the wheels backward as they compress so you may not need to move the rear backward but you should probably trim the back of the rear fenders to avoid removing them by accient. the only real way to know is to flex it out and see how much you need to move it and in what direction.

 

[chevyin]

Thanks for the replies guys. Ya, I already have the xover steering kit (no installed yet of course heh).

So basically, in your guys experience is moving the front forward 1.5" best for tire clearance? Sounds like the rear will stay cenetered.

Wish I had a fortlift to test out the flex/clearance when its together.