340 crank

I used to use the 318-3 steel truck crank in my 340 drag engines. I think the 318 cranks up to 1969 were steel. The 318 steel crank does not have the 5/8 lightning holes drilled thru the 1-2 & 7-8 crank pins. This is the reason for the rebalance as the 340-360 rods are heavier, however without these holes, the crank should be stronger. The 340's went to a cast crank in early 1972 & all 1973's.