New V8 running on 4?!?!?
 

Ok, long story so I'll make it short.

Put a new 350 in my friends car that was previously a carb motor. New motor is carb as well.

The new engine seems to only be running on 4 of 8 cylinders.

It only will run at about 70* advanced, and when I pull 4 of the plug wires off as it is running, it continues to run, without any change. Now on a normal motor usually one or two would kill it.

It has compression on all 4 *dead* cylinders. And the valves are all correct (should be anyway).

We are getting spark to all 8 cylinders, and we have changed the wires, and the plugs.

We also just added better ground strap for the motor, so I don't know.

Anyone have any ideas of what the problem could be?

What kind of carb? I've had an edelbrock do that because one float bowl was not getting gasoline due to a stuck needle and seat.

we thought the same thing. i had an edelbrock 750 which was used. i replaced it with a brand new 750. there was little if any change. please let me know if you have any other suggestions.

which cylinders arent working?

try re-adjusting valve lash w/ the motor running.