I made my own from 3/8" pl. I made an oversize triangle and finish trimed it after brazing. I made a jig so I could bore the hole canted to fit the housing and get a good fit. I am beginning to think the housings are actually cast steel. I should have done a spark test. I needed to thread one mounting hole in the plate because the F-100 housing is bigger in dia. and there was no room for a nut. From a while back. http://www.jalopyjournal.com/forum/threads/f-100-box-to-32-frame-conversion.862086/#post-9524422
That answers the question on the 34 box,it sounds like it was moved back in the frame to fit the V8,that leaves the F 1 box to use then, I don't want to alter anything so a bolt in F1 would do the job.
You'll want to box your frame to minimize flex. Box at least both sides of the steering box and leave the hole big enough to get to the mounting bolts. If your using a flathead the clearance Is very close to the exhaust header.
i have the f100 in my model A i got from Mell Gross 18 years ago, still stears great, like power steering. mine is a hopped orig eng still mec. brks [mells cast drms], his borg warner od. my steering box uses orig pitman arm and spark & throttle levers and orig wheel. model A guys don't even notice that it isn't an A box, mell does a great job.... machines the sector for the A arm, etc.
I wouldn't waste time using a model A box or a 33/34..... F1's are far supirior! Just modify the flange. I've actually cut all three ears down and re drilled as needed. No need to send it out to a fancy shop to have it modified.... You'll be happy you did it.