Torque Arm front mount help

[GhostSpyder]

First off, I just want to say that even though I just signed up and this is my first post, I have been reading these forums for help on my '77 Spyder for the better part of a decade now. So, thanks to all of you for the help you didn't know you were providing me.

My problem:
I have a '77 V8 305 Spyder that originally had a TH200 in it that I have swapped to the B&M 113001 Street & Strip TH350. Being that I am always learning about being a mechanic one job at a time, I didn't realize that the vibration I've been experiencing for almost a year is probably due to my not having the torque arm installed (because my friend and I didn't know what it was for, and it wouldn't mount onto my TH350). I still have the torque arm and have been scouring the internet trying to find a solution, but I have the round bushing arm type, which seems to be the less common of the two varieties.
I am looking into the B&M Changeover kit (http://racing.go-parts.com/bm-racing/bm ... 39817.aspx) and possibly drilling an oblong hole a few inches behind the speedometer gear hole. Does anybody know if that will work? The kits seem to be hard to find in stock and are quite expensive for being just a bracket.
If the hole-drilling idea doesn't work, I was also looking into this Spohn F-body torque arm (http://www.spohn.net/shop/1982-1992-GM- ... unted.html) with the same B&M mounting kit. The mounting seems like it will work, but I'm not sure about the length of the torque arm. Any thoughts?
If neither of those ideas are sound, does anybody know of a better alternative? Like a cross-member mount.
Also, it just occurred to me that I could try and find an original 3-hole tail housing. My TH200 tail is one solid piece (not bolt on). Would that be easiest?

Sorry about all the questions. Thanks in advance for your help.