Head sealing issue's
 

we have been having head sealing issue's well atleast with one head on are 440LSX The right side was leaking (pushing water into the cooling system) after a set of heads where installed, It started leaking within 30 miles so we pulled the heads and went to the machine shop with them and the head that was leaking was not flat so he decked the heads just to get a flat surface. We use a new set of cometic gaskets and yamabond, at first it seemed ok but after two spray passes (180 shot) it blew the same gasket so now we are thinking that the blocks deck isnt square on the side and now we are hearing that the early blocks had issue's with head sealing (metallurgy) is this true and if so how early is an early block we have #272

Was the block decked? (seems like a silly question but you never know) I'm guessing a 4.185 bore x 4" stroke.

Yes it was decked but the same shop that did the machine work did some shity work on some other parts so i am thinking it wasnt done right.

I just pulled the right head and it was blown on cylinder 2 and 8, And when i just had the heads decked he told me when i picked them up that the right head was the only one that wasnt flat and that it was worse around cylinder 2 and 8 so i'm thinking that when the head is bolted down the block is warping the head.

And yes 4.185 bore 4.0 stroke