CAn the heater box be removed and replaced off the exhaust pipe for repairs to exhaust for a 71 bug?

yep you can just run j tubes if you dont want the heater anymore

yes, 5inch angler grinder does the trick, they are only attached inside by to strips, careful not to cut the exhaust though, easy if you can feel properly with a grinder, i say 5inch because the 4inch didnt quite cut deep enough around the inside of the curved section.

depends what kind u have
there are 2 kinds 1 are just J pipes with the sheetmetal casing around them those are cool to just cut off and turn into J pipes

but tthe other kind have alloy fins all thro the inside built around the J pipe so they cant really be turned into jpipes

u can cut the sheet metal off but all the fins are still on the pipe
but i have seen that done b4 tho

as too which u have... my 71 superbug had the original heaterboxes and they had fins
but my 2 74 beetles were also both original and didn have them

all the rest are bitsa's and nothing to go by

just look down the hole where the heater hose conects if u dont have a standard muffer and u'll see if u have them or not

GL
-Joel