Projects Rear shock mounting?

What are your guys thoughts on shocks being mounted vertically from the side view and the tops angled in toward the center from the rear view, any issues? How much does the axle move forward or rearward and do poly bushings have enough deflection?
These are going on my '49 Shoebox with St. Lois Spring 4" (really closer to 5") dropped leaves with 2" blocks and the leaves are just about flat at ride height.
I'm notching the rear to get the shocks more vertical than the stock frame mounting points will be and also to get some decent shock length.
The red is just the spacers and studs incase it wasn't obvious

 

Just don't angle 'em too much.
At 45° they're only about 1/2 as effective.

 

I'm going to go as close to the leaves with the axle bracket As I can reasonably get them and they just have to angle in far enough at the top to clear my 1.75" pipes With probably an inch so of extra clearance for good measure so I'm thinking they should be right around 20°. My main concern is mounting them vertically from the side view. I know when the leaf spring compresses or droops it's going to move the axle forward a tiny bit since it sits flat at ride height but I'm not sure how much and if the bushings of the shock will deflect enough or causes binding

 

Look at the factory angle on my 57 Chevy pickup

 

Looks pretty much like my picture huh?

 

Actually 25% with the motion ratio formula [the force is 50% and the distance is 50%] there is 2 factors
The formula is "Motion Ratio squared x resistance."

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Do you want to do the non-mathematical method of calculating the shock angle. [leaf springs]
You mark a cross on both axle tubes directly above the springs/ spring pads.
Then use a string line and radius from the opposite axle tube "cross/mark" to the approx "whereabouts" of the upper pivot.

This ^^^ is the most vertical you should have the shock /coilover for a constant roll rate.
On a leaf spring rear the LH spring is the instant center [pivot] for the RH suspension and vice-versa.

This is a lot more math for complicated suspension, but this is a simple DIY method without over thinking it

 

Optimum angle is 7 to 10 degrees maximum the further you deviate from that, the more have a hydraulic sway bar instead of a shock absorber. Learned the hard way in the late 70's when we converted a 40 Ford convertible to tube shocks and didn't listen to an "old" who was 40+. Never made that mistake again!

 

There are millions of shocks mounted perfectly vertical, and the bushings take up the deviation of the angle as the suspension compresses. But as these guys are telling you, be aware of the reduction in effectiveness as you tilt the upper inward too much.

 

Dude! I met that cat once. He was **** for a fisherman but a hell of a good angler, man.