Bump Stop Question

I have searched and searched and can't find an answer I am reasonably happy with.
I am currently working on the rear suspension in my '38 Chevy half ton pickup. It consists of ladder bars, a diagonal link, and poor man's coil overs (a coil spring over a regular shock). I'm working with the Competition Engineering Rear Coil Over Kit (C2051).
-At ride height, the shocks have 3" of compression before bottoming out.
-There is 4 3/4" of space between the axle tube and frame, meaning the shock will bottom out 1 3/4" before the axle tube hits the frame.
-I need to install a bump stop so that the shock does not bottom out and blow itself up.
-My current plan is to install a stop that is 2 1/4", so that the axle tube hits the bump stop 1/2" before the shock bottoms out, leaving me with an actual 2 1/2" of compression in the shock.
-Right now I have a set of stock rubber bump stops from a tri-five Chevy that should work with maybe some slight trimming.
The questions are:
Is the bump stop engaging 1/2" before the shock bottoms out enough?
Can I get away with less? (I would like to.)
What is the general rule of thumb for installing the bump stops?

 

Any chance of getting shocks with a bit more travel?

 

Several aftermarket shock manufactures (Afco, etc) design the bump stop into the shock and sell different lengths for custom applications. If you can't apply that to your setup, then you could go thru some number crunching knowing corner weight, planned g, durometer, etc or just guess

 

I suppose that longer stroke shocks are an option, but since I already have a set of usable shocks and bump stops I thought it may be easier (and cheaper) to use what I already have.
Also, would a shock mounted bump stop work on a regular shock, even if it's not a true coilover?
Thanks for the input guys.

 

My concern with your current shocks and plan would be that most bump stops have some give to them so it could be posiable on a hard hit to bottom out the shock.

 

Pila38 checkout Speedway for ideas http://www.speedwaymotors.com/search-bump-stop.html......
these obviously work by slipping over the shaft and can be cut as needed. Urethanes have a higher durometer than rubber

 

Sorry if I missed it but what's your shock rebound measurement?
edit:
Oh assuming you have the correct shock travel, the rule of thumb for bump stops is to add 1/2" just as you have done.

 

Thanks for the link yellow dog, I'll check them out. Urethane may be a better material for me in this case.
Fenders- the shocks have 3" of rebound, 6" total travel. I'm setting them 50/50 as a compromise between street and strip, instead of the usual 60% compression/40% rebound for general street use. I might have gone 40% compression/60% rebound, but Competition Engineering recommended 13 1/2" installed height when I called them. (The shocks measure 10 1/2" eye to eye compressed and 16 1/2" eye to eye extended.)

 

" I might have gone 40% compression/60% rebound.........."

I would be very happy with that -- but the CE recommendation sounds OK.

 

I like the 40/60 set up too, but with the bump stops I would only have 1 7/8" of compression. That just doesn't seem like enough to me.

 

Fenders thanks for the help, I appreciate it. Any other opinions?

 

Any weekend suggestions?


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