look out for surging power and what may feel like a strong miss.
also check to see if there is smoke coming from the exhaust.
make sure the cam angle sensor wires are reconnected and not damaged.
i may be wrong,but doesnt the 420a motor have a knock sensor on the side of the block closest to the firewall?or is that JUST the 4g63?
when i built my eclipse motor,i was a dumbass and accidentally broke the knock sensor.i didnt realize it until i got the bitch running again either.