placement of rear shocks

[rick]

We are building a 1942 GMC with leaf springs should rear shocks be  installed  straight up  and down  and should should they be angled forward or back for best travel

[Harry]

Springs should be parrallel to the ground.
What do you mean by Up and down?

[38HAULR]

I think this refers to shocker angle. Either full vertical or angled,if I read the question correctly.  There is a scale of efficiency that applies for shocker installs, full vertical 100%. and then reducing with angle . I may be wrong here but I feel the general operating figure for most part is in the 80% ball park for leaf springs vehicles. Do some checking on stock factory leaf spring set ups and you will get the idea.........Frank.

[enjenjo]

The more vertical the shocks, the more effective they are. The more angled they are the less effective. I generally angle them 15 degrees or so from vertical. If angled forward or back, they are more effective on wheel hop and brake tramp. Angled in is better for sway control.