Long story short my car ran great, but i just installed the heater core, and put everything back together, once i started the car again, It had a low idle, started
stalling, when i step on the gas it wont rev past 3000RPM, i even put it to the floor once, reached 3000 then chugged and nearly stalled. it struggles to move and i have a large amount of power loss. cant get it to move more than 15mph. I just replaced the fuel filter, checked my heater hoses to see if i had them backward, checked the spark plugs.... no help. im hoping i havn't busted a lifter, worst i did while doing this job was drop the hood into the engine while trying to put it back on myself... any ideas what i did wrong?

its a 1980 camaro z28
3 speed auto w/ b&m shift kit
350bored(.030) over

 

sounds like a stuck choke...

 

I'd start looking for a vacuum leak. That system was disturbed when you had it apart, or, you damaged something when the hood got dropped on the motor. If it ran fine before you did the job, then, some issue related to the job being done is what's causing your problem now.