305/350 crank

[Steve Williams]

Originally Posted by BillK

Steve,
Other than the balancing there is absolutely no difference between the two crankshafts.

I just looked through some old balance cards and found a 305. The piston and pin was about 60 grams lighter than most of the stock type 350's I have done. 622 grams compared to 682 for the 350 If that is not enough to make you believe that the 350 crank needs to be rebalanced to use in a 305, then I don't know what is

Bill,

The differences go further than just balance. The use of a 350 crank in a 305 has been done several times in our shop and with a cast replacement piston, I never sent one out for balance. The advice of my crankshaft guy was that 305 cranks rotating 350 rod-piston was a problem, but 350 crank in 305 with cast piston or cast replacement was not a problem provided it was a stock rebuild, stock intended RPM range. As far as the weight difference between the two engines, I don't recall what the exact number was, but it seemed it was much closer than 60. I want to say it was 46 or 48. I can tell you that the 305 crank, if used in a 350, will have a bunch of mallory in it. Built one for a customer who supplied this balanced assembly. He knew nothing of what the crank was until we looked it over closely and told him. The amount of mallory was a dead give away that something wasn't right.