since I acquired my '72 I have been going over everything trying to 
get more power out of it such as changed plugs, points, vacume lines, 
oil, filters, set the valves and timing.  It now tops out at 55 
rather than 35 but this still isnt enough, if I hit a hill I can 
barely hold 50.  I would like to make a trek across michigan tomorrow 
but doing 50 in 75 zones would get me killed.  What else should I 
check?  I havn't done a compression test but it dosn't smoke at all, 
the bus will not roll on a hill in 1st and is verry hard to push in 
4th with no aparent soft 
spots.  could richening the mixture help me out?  where is the screw? 
 I finally decided that the engine is a standard, carbureted, '72 
1700.   I have a fair amount of power untill I hit 3rd but when I 
shift to 4th, there is nothing left.  The engine stays at low rpm's 
and wont wind up any further.  If you have any Ideas as to what the 
problem could be please let me know.  I dont want to end up taking a 
train to Kalamazoo. 
 thanks.
    Ed.