Youre getting good advice in here regarding which balancer to buy. Plenty of people run blowers on stock cranks and have no issues but some people rip the snout off of them. Any time you add more power, its a gamble. I did it for years on a stock bottom end 302 that went from my fox to my sn95 before I dropped a valve and then switched to turbo but I also was only making like 8psi (375whp) and didnt have the belt cranked super tight. The more boost the more load placed on the crank and the more chance of the key shearing, or the balancer cracking at the keyway or breaking the crank. The better the balancer, the less chance you have of the cracking happening but even if you use a special blower specific balancer, breaking the snout is always a possibility. I can tell you from experience, breaking a crank is no fun. My turbo 306 broke on the inside edge of the #1 journal and took out the whole front of the motor... Timing cover, block, oilpan, waterpump all destroyed in a matter of seconds. Mark and Strokeme have experience with probably thousands of builds. Their advice shouldnt be taken lightly.