I have just rebuilt the 350 in my van I believe everthing correct as far as cam timing , dist timing goes . my problem is that the vacuum hose routing diagram is missing I am not sure where the hoses should go and the local chevy dealer says he doesn't have books on anything this old . help !!!!!!!. Van is 1989 got a code 33 and have replaced MAP sensor no change, however if Map sensor hose is disconnected van will run maybe 4 mins. and then quit. Recently copied the VECI label off another van of same year seems like all the vacuum plumbing was correct same problem exists!!!! HELP ME... :mad:

You don't mention much about the vehicle (doesn't have any books 'how old'?).
You can get a Chilton manual pretty cheap and it should be in there. I posted '97-3500 Bad morning start' and haven't gotten too many answers yet, but Fuel pump caused similar problem for me.