sb crank numbers?

The 340 external convertor is special just like the balancer. 3751841 would be a 318 crank and all 318 LA's are internal balanced. The 318 crank is a direct bolt in as far as size but it needs to be rebalanced to match the weight of the 340 piston and rod. I put a '65 poly 318 crank in my '73 340 because all poly cranks are forged.


Chuck