Blaster cylinder questions

[devinmadssen]

Okay I've been posting quite a few threads and been getting great answers. I have an extra blaster cylinder and was wondering why there's 4 holes drilled in the bottom half of it? The picture is from Google but it's similar to that, was wondering what it was for?

 

[OConnor Racing]

It's an early cylinder. I'm pretty sure they did it to reduce noise and vibration.

 

[devinmadssen]

Okay thanks a lot kor I appreciate it!!