318 intake swap, now no spark

Hate to admit this but when I put a different manifold on my 273 I didn't remove the
dist. cap and just pulled it out and sat it on it's side thinking nothing would move. Well,
it went in just fine and when I went to fire it up it wouldn't start - like yours. Kept
pumping the gas and moving the timing around - then a big boom and my one month
old new right side muffler blew apart. I put the dist. in 180 backwards - the rotor spun around when I sat in on it's side.---- needless to say - please take off your cap and check that number one is on number one.(have to pull of the driver's valve cover, manually turn the motor over and make sure the timing mark comes up at the right time
and not 180 out). AND YES - it was a big boom and my head was hanging low!!!