For the Bay peeps out there looking for cost efective gearing...
My Fav swap (IF you have a larger engine as mentioned above) is a 091 78-79 Bus 6 rib trans into a 68-71 Early Bay.
For me this is the best stock swap. Take th e091, swap your bell housing and trim the end of the input shaft (if you dont it will bottom out on the crank)
swap your nose cone mount and instal the trans. The trans is a little longer so you may need to open up the moustache bar holes.
as seen below
The shifter may sit a little more towards the front of the van due to it's length but you can shorten the front shift rod under the drivers comp if you like.
This taller gearing makes a big difference as well as helps if your lowered and running smaller tires.
I run this combo in my 68 Westy.
If you have more $$$ more power and some skill... A Porsche 915 5 speed is great!
I have that in my 69 Panel with the Porsche 6cyl (you can use this trans with a T1 or T4 engine w/adapter flywheel)
In fact that 915 although not a great shifting trans allows my bus to cruise at 85-mph no prob with the 6cyl and it's only 170hp.
But bang for buck go 091!