before rebuild, motor had a knock but would start and drive fine. Rebuilt motor and now motor barely starts and at idle it misses and will only run for about 20 seconds before it stalls.When you give it gas it will not increase rpms and in fact will eventually lead to a stall if you continue giving it gas, once while giving it gas it also backfired on me. Also as soon as the engine stalls you can hear a clunk inside the air flow meter unit(dunno if that is anything). I'm early in the troubleshooting so any help would be appreciated.

 

check your timing.

 

checked timing and in the brief time it will run i see the mark between 8 and 10 degrees. at first I thought i was 180 out so I tried pulling the distrib and turning motor over 180 and it would not run at all. so dunno looks like timing should be ok

 

Are all your connections to the intake on right? See if its sucking air anywhere. And as for checking the timing, you should have turned the engine over before you put it back together and checked it again. I would strip the front and check it by eye. Did you double check everything twice, cam bolts, etc? Double check everything...

 

Any fuel smell? The reason I ask, when I reassembled mine, I inadvertently mixed up the fuel return line to the vacuum port for the brake booster - fortunately missed putting the vacuum line on the fuel return port (no contamination) but found the problem (finally) by fuel dripping from the return port. The engine would pop off but not run for more than 20 sec. Make sure you have all the vacuum lines connected!

 

i just got done doing this the other night you need to make sure that your at tdc on number 1 pull the dist. out it should be pointing basically at the front cover when installed its eathier timing or like the others have said maybe a vaccum leak