puking antifreez w/ new motor
 

We just got my new 306 fired up it wont hold idel and is puking antifreez when we shut it down after only runing maybe 30 seconds. could this be a air lock or a stuck t-stat. or worse a head gasket but it isnt bubbling when it is running, one time it forced it out of the overflow with the rad. cap on, the next time we left the cap off and it really shot out. please help..

Re: puking antifreez w/ new motor
 

Timing.

T-stat closed will puke it back out the rad. Not installed the right direction can do this. Does the upper hose get hot at all?

Correct rotation water pump?

Re: puking antifreez w/ new motor
 

A friend of mine had someone build a 460 for him and they didnt check the heads for cracks. It had a cracked head, and as long as it was running it didnt blow out any water. Had a 5.0 in an older Capri and it had a cracked block thru one of the middle cylinder head bolt holes in the block, it did the same thing your describing. Probally isnt your problem just food for thought. Hope you figure it out soon.

Re: puking antifreez w/ new motor
 

If the T-stat is installed correctly and you have the correct rotation water pump then unfortunately it is a head gasket leaking compression into the coolant passage

Re: puking antifreez w/ new motor
 

First thing I'd check is the water pump, make sure it's a reverse rotation, and that the thermostat is working, and installed in the right direction. Second, pressure test the cooling system. Also look for water in the oil pan, that's a gimme that you're tearing her apart again.