I need an education on factory transmission crossmember differences

[cboss70]

I am in the process of restoring individual parts for a 67BB 4spd, 69SB AT and a 70 Boss 4spd. I have a number of cross members with slight differences and am not sure what goes to what. If you look at eB a lot of ad's say everything fits 67-70 so that lessens my trust in the sellers as a whole.  I have a few versions, 1. One looks like a standard 67-70 contours but has two maybe 1/4 holes drilled through the center lip
2. Have others with no little holes as above
3. A couple where one side of the cutout goes in further on one side (mounting bolt to body mounting cut out area)  and the transmission mount slots in the center are more elongated than on 1 and 2
4. The last one has two frame mounting holes on one side and one on the other- probably fmx/c6 69/70.

I'm more familiar with the 65/66 which are basic but these have me second guessing myself. Can someone shed light on the "visual" differences between the year and applications? 

[Special Ed]

67 - 68 big blocks 4 speed have 390 std stamped on them and are very hard to find that don't have pitting and 69-70 big block 4 speed has 390 std and 250 stamped on it with longer holes and are hard to find and no repo made. 69 351 w auto is stamped 351 and c6 big blocks are 3 hole type triangular shape also hard to find. 67-70 small block 4 speeds are easy to find and are thinner metal and not as tall and heavy as big blocks. We have some photos on our ebay store of these.

[kingchief]

Might be interesting to post 65/66 stuff also.

Just asking for info.

Steve

[TLea]

Ed the late 68s with 2 1/4" exhaust (cj) also use the 69 style with the 250 stamp   Slotted holes also longer than 390 version

[69mach351w]

I understand this is an old thread, but I found a cross member and wonder if it is a C6 A/T cross member. Thanks for any help.

[Special Ed]

Looks made up to me not factory

[69mach351w]

That's was I was thinking to Ed. WCC has a repop looks just like this one.
Appreciate it 

[68stangcjfb]

Here are a few pictures of a C6 crossmember.