What Motor with a split gearbox

Hi just wondering if anyone could tell me what will fit up to my 57 beetle split gearbox or am I better off putting a later gearbox in it?

Cheers John

all 6 V motors will fit

if you use 12 volt motor it has a larger dia flywheel which will run on bell housing

I have a 66 beetle with a 6v gearbox. I ran a 1776 12v engine, and all i had to do was grind out the bell housing using emery flapper wheels on the drill...
I converted the whole car to 12v at the same time.

Here is the thread i started:
http://forums.aussieveedubbers.com/viewtopic.php?tid=106941

Here is my members ride - look about half way down the 1st page
http://forums.aussieveedubbers.com/viewtopic.php?tid=106947

with a bit of machining a 6V flywheel will go on a 12v motor. I mean, as the split box can't handle too much of an increase in power then the 180mm clutch of a 6V flywheel ain't really gonna be an issue.