318 DQ's

yep 9.2 is about what an early 340 gets with a head gasket change
the late 340 or 360 dies with the 340 cam as attested to by others above
do not believe adverts for compression ratios
(not that you can't make a long seat duration cam work- but not with 2.76 gears AND low compression)
I've tried advancing the cam every which way, advancing too much and the intake opens too early and you get exhaust contamination- piston coming up tries to push exhaust out your carb- not good
you can do some distributor advance work which helps but bottom line it is'nt the right cam for lower compression