I bought a 73 400 pontiac a few weeks ago. The man showed me a video of it running bout a year ago. I put the engine on a stand so I could change freeze plugs do some cleaning and maybe paint it. It turns over good by using a breaker bar on the crank bolt. Hooke jumper cables to it poured a little in the carb cranked it and it fired up for just a second or two. Filled carb bowl this time and tried to crank and barely would turn over. I pulled plugs out hooked up cables and it spins over great. Put two plugs in, one each side it won’t turn over hardly at all. Moved plugs to other cylinders same thing. So I bought a new starter today, made no difference. Starter is shimmed out so it’s not binding up the starter. I pulled valve covers off and all the valves move when cranking over with plugs in it. It getting oil thru the push rods so I know it’s building pressure. I’m out of ideas, hopeing maybe someone has seen this before. I did pull exhaust manifolds on both sides thinking maybe they were stopped up, no change. Y’all got any ideas? Thanks in advance.
