pretty much the motor is in the car, but i have come to realize i forgot to put these things in ...i have not started it yet.
how important are they on an engine that has head studs?
i really dont want to have to pull this engine out, cuz i had to do it in my garage and it was not an easy task to say the least...
just would like some input from those more experienced than me...
this is a 427 ls1
10:1 CR
AFR 225s
248/252 .630/.630 114+2
will be running a 200 wet through it as well.

 

No sure what everyone else would say. But those Dow pins help center the heads combustion chambers to the center of Cylinders.. I would take it down and re-install them correctly.

You didn't state what car it is.. so maybe you can just pull the heads with the engine in place..

 

+1 those pins are the only thing keeping that head centered and true. Sorry to say but they must be put in. your gonna need new headgaskets too being the ones are the car are compressed already. It happens....

 

+1 well if its an f-body its gona be a hard job removing the heads vettes are easier.
I think for a 427 an expencive engine it is worth it to install new cylinder head gaskit.
my advice is not to start the engine with the haeds not centered.

GOOD LUCK.