Hi Anders,
i have done a fair bit of fankensteining stuff together for testing. make sure you ground that control box well or you may have a spark problem.
i would like to also recommend removing the K frame, and thoroughly degreasing it. caustic oven cleaner works very well on automotive grease, scrub with wire brushes, then rinse with water to neutralize.
then look at all the welds holding it together. what i did with mine was add an 1/8" skid plate/ stiffening plate to the center of mine, added gussets to the steering box mounts, and then i seam welded the K frame around its entire perimeter. i recommending welding it all with the bare K frame installed in the car as a fixture to help prevent warpage.
go to
www.firmfeel.com and look at the pictures of their reworked early A body K frames. i bet you could duplicate their efforts to stiffen yours up with a little effort.
these cars are flexi flyers, and anything that can be done to stiffen up the unibody, and force the suspension to do its job is a welcomed improvement. there is a right way to add subframe connectors as well. it involves levelling the chassis before welding them in so your not adding in twist to the body structure. the methods on making them vary and all are good ideas.
i made mine out of 2"x3" rectangular tubing that was 1/8" wall thickness it was attached to 1/8" gusset plates on the transmission crossmember to spread the load from the connectors. i then rerouted my parking brake to inside the frame rails. i had to slot the rear footwell pans to run the connectors and when you lay the tubing 3 wide 2 high they only stick up thru the foot wells 1/2" . the carpet covers this up where its not noticable at all. additional padding on either side really hides them. my cost was about $35 in material.
if you decide to do this, let me know, i can send you pix of what i did, including the rerouting of the park brake cable, this is a big improvement in how the car feels and handles. if you look closely at my avatar, you will see the boxed in front and rear torque boxes i made from 1/8" thick steel plate, as well as the subframe connectors. i even drilled 3/4" holes in the bottom of each subframe connector in 3 locations each as drain holes trying to make everything appear as stock as possible.
Matt