Frame dimensions...67-72 & 73-87

[pcmcobra]

Looking at Chucks pages, he posts a nice diagram and measurements:
http://www.chuckschevytruckpages.com/framespecs.html
I am not sure if this applies to 67-72 frames also.
I am trying to find a nice tranny crossmember for my 86 truck. I'm going with a 4l80.
Several companies offer tranny xmember for 67-72:
http://www.performanceonline.com/sto...cat=461&page=1
http://www.classicperform.com/Store/...uck/CP9427.htm
But the sites do not list measurements/specs. I have emailed them, but no reply after several weeks.
So, that's my situation. I want to find an aftermarket crossmember to fit the 4l80, preferably use the stock holes in my frame, and have some clearance for exhaust. I would prefer not to use a "kit", since I have no welder, but would consider one.
thx