Others will have more experience and guidance, but you should make sure you are at TDC on #1 on the compression stroke... common problem is distributor is 180* out of phase... you can pull the distributor and rotate 180, or rewire the cap with #1 as #6 and so on...

That's the easy solution... if the internals are wrong, though you'll need to start digging deeper. Starting with a visual of the timing set (I believe the dot on both crank and cam sprockets should be at 12 o'clock at #1 TDC) then on to degreeing the cam and checking the rest of the valve train...

I'm not the expert on this stuff but this should be a decent start... others will chime in that know more than me

Good luck...

-Chris