Yea and sometimes you over look stuff.....sounds like its 180% out ..need to check vavle timing in according to where crank and cam are .....GM MAster tech for 25 years ....they can be screwy ,,,,,in stead of on the intake stroke it could be on the exhaust stroke ,,,,,,,glad to hear you didnh`t try to start and did it by hand before it srewd everthin again ...good luck my daughters nissan had me going for awhile
bg
November 2005