The 454's(7.4) have the same distributor and firing order as the smallblocks(5.0, 5.7, etc). Same ECU wiring for the throttle body injection too.. I've had a few of these over the years (the 7.4 that powers my camaro came out of an 89 pickup). Take the number one plug out and bring it up to the compression stroke for #1.. Then take the cap off and see where the rotor is pointing.. Someone may have had the distributor out at some time and dropped it in in a different position than the manuals say.. The firing order is still the same, just start from whatever post the rotor is pointing at... The distributor turns clockwise.. Cylinders 1,3,5, and 7 are on the driver's side and 2,4,6, and 8 are on the passenger's side... Also if you're sure you have spark and the wires and everything are on right, take the air cleaner off and crank it.. You should see a good spray of fuel coming out of the two injectors.. If not you need to check for fuel pressure.. 9-13psi is what you'll be needing... They will run on as little as 4-5psi, but they'll run reall crappy... The 7.4's always seem to run a little on the lean side part throttle and that will get a lot worse if the fuel pressure goes a little low for some reason...
Also, don't waste your time trying to scan it... It's pre-obd2 so it won't really help you much, especially if it doesn't start... One way to see if the light works is to just turn the key to the on position, the light should be lit...
Hope some of this helps...
Jason