Having trouble getting shifter to select low gear

Not really, looks like you have a transmission that doesn't have the cast in ears for the floor shift bracket to bolt to and its been modified to bolt to the transmission pan instead. That should work though but its only using one bolt and probably letting it move from adjustment. I believe if you extend the homade mounting bracket to use two bolts so it can't move and then readjust your linkage it will work.

 

Probably not, they quit putting the bracket mount on some of the newer transmissions. Although i have seen some older ones without them too. If you car was originally a column shift and was changed over to a floor shift it may not have came with a transmission with the bracket location.

 

Here's where the bracket would bolt, in the two holes on the tailshaft.

 

Looks that way, I would have another support brace welded to that bracket so it can't move and that should work.

 

Yes if you post a picture of it I could tell.

 

Looks like a 7 1/4 to me. How many bolts on the rear housing cover?

 

I had similar problems with a shifter/transmission/body mismatch.
I had to drill a hole on transmission shift lever to give the lever a little more throw.
Start with the bracket mount and see if it improves.

 

I can't see how that homemade piece could move enough to cause your problem.
I did have the same problem with all OEM parts build ( column shift to floor shift change ). My shifter hit the console opening before getting low gear. I removed the console and still couldn't get low gear.
The factory service manual states to set up the shifter linkage adjust in neutral position. Do that and see if you get both park and low gear ends of travel. It worked for me.

 

Yes, looks like a 7 1/4.