Inliners International Forums General Discussion Engines identification wizards-what year is this 292??

I have never had much luck using the casting number, nor the stamped pad numbers, so what year and where did my 292 come from? [/b]Stamped pad number: FO 7111BG block casting number:3921970 date code number: CON2 F248[b]--I can only figure out it was cast June 24 in 1968,1978, or1988. If I take off the timing gear cover and look at Leo's book I should be able to get the right decade from how the timing gears are lubed--but, I don't want to disassemble anything on the motor 'til the project can move under it's own power. and I'm certain a wheel don't fall off or worse...Help me ...please?