Weird starting problem after DE swap

[mx32nerDOTcom]

I have to hold my key in the crank position for like....8-20 seconds sometimes to get my car to start...Im not really sure what would cause it, once it starts, it won't idle, i thought maybe the idle was too low, would that cause it not starting right away? any help is appreciated

[lakersfan1]

Two most common problems immediately after an engine swap:

1) Not enough grounds from the block to the chassis/battery.

2) Open/unused vacuum ports on the intake manifold.

In your case, I'd look for any vacuum nipples on the intake that aren't hooked up.