You can also use a 901 front shift five speed from a 65-69 911 w/out too many issues...915 sideshift will NOT in your application. 68 and later baywindow buses (we'll call em buses even tho they are turds if they aren't splitties

) used type "4" trans similar to a 914 transaxle.... You will need to swap your rear suspension to IRS to use the 911 trans (see below), a 901 is good for 350+HP and equal torque so you wont bust it hauling heavy loads.... IT really depends on WHAT you're wanting the 5 speed for...MOST 5 speeds keep the 5th gear ration the same as the stock 4th so you get no overdrive...you just get quicker acceleration and easier time to haul more weight... Now if you DO find a 5 speed or a "freeway flier" type trans (4 speed with taller 4th for lower revs) you gotta be careful in the hot weather cuz the Type 1/2 engine's cooling fan is meant to turn a minimum speed and when you overdrive the trans, the RPMs come down and you'll cook you motor even tho there's less "load" on the engine...remember the fan keeps it alive......so if you DO go for an overdrive, you REALLY need to tap the case for full flow and put a fan-powered oil cooler in the system to make up for the increase in heat...DO NOT use a oilpump cover type "cooler" adaptor as they only cool about 10% of the oil. Another handy tip is a deep sump from Berg or a similar company. More oil capacity = more area to disperse heat. Hopefully you have a dual relief case, but at the very least add an oil cooler if you overdrive your trans with whatever choice you make...TRUST ME, I've dumped enough Type 1 engines on the pavement....
You need to improvise on the shift lever (simple mod, you'll know it when you try to put the stick in.... its just a bend or 2 to clear the parts in the bus... you can keep the swing axles if you weld the back 1/2 of an IRS trailing arm to the spring plate *OR* weld IRS pivots to your torsion housing (its really NOT that hard if you find someone who welds cheap) you'll need the IRS trailing arms and brakes/backing plates/etc.... *HINT* get them from a 77-82 porsche 924 at an ecology junkyard and NOT a VW wrecker...same parts, ecology will tag you a lot less than a "VW guru" for the same friggen parts.... Also, Type 181 and 924 CV joints are 100mm and should work in place of the 3x expensive 911 CVs (but double check the splines, its been 10yrs since I did this sh1t)
Its definitely do-able.....Check this info out....
http://www.aircooled.net/gnrlsite/resource/articles/porsche5spdconv.htm
http://www.tunacan.net/t4/tech/trans.shtml#t2
Type1 and Type 2 are essentially identical in the rear end except for the alpine reduction boxes on the transaxle. If you use a 901 you'll need to flip the ring and pinion or you'll have 5 reverse's and 1 forward gear hahaha...
Also be sure to check out
www.shastasnowtrip.com if you think you got the huevos to hang for a week with REAL Type 2 people that drive their buses thru terrain most 4x4 guys would not drive thru, and survive each time...its nuts but its a must-do experience if you're hardcore dubber like myself and can do 2900 miles in 7 days.... Its a hell of a good time if you're a masocist...pussies need not apply.... Also check out
www.backroadbus.com and
www.rustybus.com
I know this is a lot to absorb but I KNOW MY SHIT so if you want good info, email me and I can help you out. I always got love for fellow dubbers.... stay cool...
J
*NOTE* this info came from my son not me.... if you want more info PM me and Ill give you his email address.... If you're in SoCal he might be able to help you do the swap as well...