273 copper head gaskets SCE

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heads are milled .003 to flat surface

my pass 273   head milled  2023.jpg


my drv head 273 milled 2023.jpg
 
the machine shop said they took off .003 to make the heads straight and both the machine shop and I did the feeler gauge with a straight edge which showed no reason to leak . when I told him I used 40 year old nos head gaskets he said the material break down. and I even seen a video on youtube the showed what happens when the material breaks down between the water jackets . just what happened to mine . .. IF that wasn't the case then it was a torque issue .

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intake is installed ...need to lash the valve again and bolt the headers on . won't be long now till I fire this beast up again ! lol
 
Cometic will make you any size gasket you need, i have a 273 that is .70 over and they made me a gasket that fit my bore size exactly.
 
Do you plan to retorque after a few heat cycles?
After the first fire up I checked the timing and it was way off like the distributor moved alot . 13* initial , 14* mechanical, 27* total.. I strongly believe this why the head gaskets blew 2 times. DETNONATION. never heard any signs of pinging even when lugging it in 3rd gear ... dist advance can hooked up . timing should have been run at 34* total ... 20* initial 14* mechanical.
 
After the first fire up I checked the timing and it was way off like the distributor moved alot . 13* initial , 14* mechanical, 27* total.. I strongly believe this why the head gaskets blew 2 times. DETNONATION. never heard any signs of pinging even when lugging it in 3rd gear ... dist advance can hooked up . timing should have been run at 34* total ... 20* initial 14* mechanical.
Advanced timing can lead to detonation, retarded timing usually results in poor performance and hotter coolant temp.
I was curious if the directions said to retorque.
 
AAt

At this point
I'm going to pull the valve covers off and check the head bolts underneath the rocker arms to see if they need more tweaking if they don't the bottom set of bolts by the headers I will leave alone because I am not pulling off those headers again
 
I'm going to pull the valve covers off and check the head bolts underneath the rocker arms to see if they need more tweaking if they don't the bottom set of bolts by the headers I will leave alone because I am not pulling off those headers again
I have confidence that these Mr gasket 1121 g will seal that head. I'll watch the coolant level if it continues to go down then I will definitely pull off the headers and tighten the lower bolts
 
my 273 beast never pinged... started perfect... never fought itself when starting ... temp ran cool as a cucumber. and that is with the timing at 27* total timing. go figure. and it screemed like a angry beast !
 
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