I raced SR175's when new and have owned many of them through the years, I can agree.
They did not have compressions releases nor were the heads drilled for them.
It was real popular in the early 1970's for owner to install them, they were sold at about
all the dealers who raced.
Hope this helps.
Thanks
Richard Clark
Questions? or need Bridgestone parts? call:
Richard Clark
812-944-1643 8am-6pm EST Weekdays