I know this an f-150 forum, but maybe somebody can help me. I have a 95 F-250 with a 460. It won't start unless you boost it with a 200 amp booster. Have replaced battery, and starter, Turns over like a champ, but won't start unless you boost it. no spark unless you boost it. my 6 amp charger won't start it, jumping it from another vehicle won't start it. ONLY my uncles 200 amp boost will get it started. Once it starts you can drive it... it occasionally stalls out and needs to be boosted again. HELP!!!

 

I'm thinking ignition control module. It can be traced from the distributor to the drivers side fender skirt. I know this is a common problem with the 302/351. I would remove it and have it tested at parts store. Hope this helps.

 

I have already replaced it Drove it some more yesterday, runs fine, once I get it started... Battery light is on now, alternator is working and charging though... New battery, new Starter... putting a new Alternator on tonight...

 

this is far fetched but I have a question for you. Does your ignition swith have a lot of slop or play in it?