Axle position 64"s/63"s...front mount 4" forward?

[lochenjons]

I['ve searched and it seems like most people are moving the front mount 4" forward with their 64"s spring swap? Would this move the axle back considering 64"s are 12" longer than stock? Basically, on my '77 k5 there are 2 sets of 2 rivets holding the bracket for the body mount underneath the frame. The rearmost of those sets of rivets are the first set of 2 rivets holding that bracket attached underneath the spring mount to the bottom of the frame.

Kinda like this (looking up from below the truck, these are underneath the frame):


.. ___..___ ..

The middle ".." holding both the body mount and the spring mount to the frame. If I move the spring mount directly underneath the body mount making it:

..___ .._______

Then itll be 5.5" forward. Too much from what I'm hearing.

But if I stager it like

.(body).(both).(spring) ____.(spring).(both).(body mount)

Then it'll be exactly 4" forward. This sound right? I can go out and take real pics if you want but basically all I need to know is if you guys are moving the front spring hanger mount 4" forward? And not that it makes a whole lot of difference, but is this putting the bottom rivets like my genius illustration above on your guys k5's? There might be a difference between 77 and under and 78+ tho

 

[Hogback Fabrication]

What are you trying to do with the wheelbase of your truck?

You can move than front mount pretty much anywhere you want to get the wheelbase you want. You don't need to reuse any factory holes if you don't want to.

 

[lochenjons]

What are you trying to do with the wheelbase of your truck?

You can move than front mount pretty much anywhere you want to get the wheelbase you want. You don't need to reuse any factory holes if you don't want to.

I want to keep it in pretty much the stock location since I still have a body on my truck . But It can move back an inch, maybe two at most. I read that 4" forward kept it close to stock, but that doesnt seem quite right if the springs are 12" longer

 

[rdn2blazer]

Im going to try to explain what I have done with some pics to help. I took these pics just a second ago. DISREGARD my shackle angle as there is no weight on the truck these are just springs hanging from the spring hangers. My K5 is a 73' so I dont know about other year K5's and if there brackets are in different locations. I would think all would be similar.

63 or 64 inch springs not sure of the exact length but Im going 63 as a refference, so 63 - 50 (stock spring length ?) div. by 2 = 6.5'. refference number.

The Front Spring Hangers are located back from a cross member. If you measure the span of the rivet holes center to center on the lower suport bracket thats under the front hanger, they should measure the exact same as the center to center of the cross member their just behind. Infact the front 2 rivets of the support are actually the back 2 rivets of the cross member. In the second pic the 2 holes to the right are for the factory bump stop bracket, disregard those 2 holes.

I moved the front hanger forward right under the cross member since the holes match up near perfectly. It went forward exactly 5 1/4 in. So if you look at our ref. value Im 1 1/4 back as far as axle center line.

The Rear Hangers. I baught ORD hangers but Im now going to be running these on my burb instead, Ive got DIY shackle flip buckets coming.

In the pic of the bucket it is moved back from stock position the width of the holes. Front holes go to the rear holes. That measures 6 inches. So there is only a 3/4 inch difference between the front and rear hangers vs what they each moved, and thats towards the rear.

I have not bolted the rear up just yet. I want to finish everything, get the weight on the suspension and fine tune the shackle angle, then bolt it up where the angle is at its best. If I have to redrill holes or slot the ones that line up in the pic I will. you can see the center pin is right about center of the wheel well, and as there is weight add to the truck once its on wheels the shackle angle will improove.

The suport brack on the bottom of the frame for the front hangers, I ground the radius in the center of the bracket higher so I could get a socket on the bolt without it being on an angle. I also capped the outside, you can see in the first pic. it goes all the way down and is fully welded to where the bolt goes thru its double thick. Also welded gussets inside the cross member support for added strength, you can see that in the 2nd pic. Hope this helps.