Technical Pinion Angle & Moving rear end Back

My coupe’s wb is 122” from the factory but with the lowering blocks it has moved the rear end forward approximately 1.25”, which then causes the driveshaft to hit the yoke at the back of the trans. (thanks previous owner)



So I need to cut the blocks to move the rear end backwards. I also need to shorten the lowering blocks by around 1.5-2” in height as they are just too large.

If I do a cut of equal angle & amount on top & bottom of the lowering blocks, I believe it should move the rear end backwards, hopefully not change the pinion angle. Does this sound correct? Similar to the red lines below:

 

Crap that’s a lot of block

 

The stance is killer looking but it’s just too low.

 

too low?
Crap no.
Just a lot of block

 

Wasn’t this issue talked about a year or so back?

 

Time to dis- assemble, evaluation, RE-DO !

 

Probably was, I needed to re-confirm my thoughts before I open up the can of worms. I’m finally ready to start in on it now!

 

Them rear springs are probably crying.. I would remove blocks and go from from there.

 

There used to be Pinion angle wedges as they was called with different degrees.

But thats a LOT of block !

 

MAN !! That's a buncha block .........
6sally6

 

Check please!

 

Good opportunity to clean up that scrub line issue, too.

 

Post a pic of the spring hangers.
Could be possible to shorten them and use less block

 

Too much block . You can always redrill the bottom block centering hole to move the diff. Back some . If you remove a block you’ll see a hole which corresponds to the spring retention bolt . Redrill it and move it exactly where you want .

 

^^^^^ But is it a solid block???

 

It looks to be one block, but fully solid I don’t know. With my luck I’d cut it only to find it hollow.

 

Leaf Link it, and add override bars to handle brake torque

As it sits with those blocks any acceleration "thrust" or brake torque will cause the driveshaft yoke to "Liberace" the transmission tailhousing.
Adjustable upper override bars can alter pinion angle etc and multiple holes can be drilled to adjust ride height.

This is from the Chrysler bible

 

No need to cut to find out.

 

But you really need to rework things as mentioned. Your scrub line is BAD!!!

 

Also you don't have to cut blocks on both sides or at a angle. Just cut one of them in half and save the other for a doorstop.

 

I’ve used 4” solid blocks to lower our 40 Chev for Bonneville. It has a Pontiac rear and stock leaf springs. I put in a front leaf spring wedge for caster alignment to correct the lean. With the wedge I used I needed a longer top on the “pin” bolt that held the spring together. I made that. It was the easiest thing I could think of. I needed an additional wedge under the spring/shock mount in the opposite direction to keep the u-bolts inline.

 

I was going to mention the scrub line way back at the start, but I decided not to. It always seems to end up in a stupid discussion because peope don't really understand it.........

 

That's scary. How about bags and truck bars with a Panard bar. You'd solve a bunch of things wrong with that current set up. Yikes.

 

That getup wouldn't last a month in Wayne County, MI.

 

as above suggestions apply, how would you ever change a rear wheel?

 

Blocks don't need to be altered, you can just drill a new alignment hole in the axle perch to change wheelbase. Wont solve scrub line issues, or eliminate that thick block though.

 

Could shorten the driveshaft ?

 

I'd just remove the blocks, put it back together and start over.

Start with a fresh slate, see if you have room to shorten shackles, even an inch would help.

Then build blocks if you need to, I'd build my own blocks, then you can put the holes where you want them, build the pinion angle into them etc....

...

 

Make some "practice" blocks out of wood and try them before you start cutting your metal blocks.

 

Ditch the blocks. Tweak the shackles and reverse the main spring eyes. Evaluate from there if it needs something more to get it down to where it looks good.