LocWire HD probs, expert help please

The one thing you might check is the dowel holes. The gasket will fit tight on them and the head will fit loose and cause the head not to alighn on the gasket perfectly:) Large dowel holes in the heads lets the head float around to much and not index verry well.
I also know that if the reciever groves were put in the head with one of those hand operated tools they dont work verry well and the primary seal at the bottom of the grove has chatter marks and is uneven it wont seal verry well. I have my oring groves CNC machined into the heads and are .009 deep with a nice finish..Ive never had a problem and use no extra seal. FWIW
 
Had a similar problem a few months ago.
Do you have a friend that does emission testing?
Have him to put the sniffer over the open neck of the radiator.
You may find that you have some exhaust gases coming out the radiator all the time. Meaning headgasket not sealing for what ever reason. Then when you go under boost the exhaust gases can't escape fas enough so it blows the water out.
I had 175# +/- 5 on all six cylinders but my radiator flunked emissions.

Gary
 
headgasket problems

Tried ARP studs yet?The clamping force is much better and if anything will help seal and compress the fire rings studs will.
Rod
 
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