The reason for using using only 1 gear is because not shifting is faster. The 400's are stonger than the glide's which is why even some blower cars use them. (Most blowers run a clutch). Your tire speed is above 100mph at 8,000 and about 70mph at launch.
Alan Pope is the man when it come to glides!!! and convertors!
Here are several pics of a chain off the tail shaft.
http://mudracersassociation.com/foru...n+drive#p15272