Tuning a fathom for long distance surfcasting tossing 4-8oz leads and bait, a cast generating enough rpm's, can have its brake blocks reengage from their disengaged position, inhibiting spool speeds therefore decreases distance. To help rectify I removed 4 excess b/blocks and left 2 opposing ones behind to apply friction.
This lead to another issue rearing its head, only this problem causes unruly spool speeds increasing crack offs and crows nests. After inspection, I found wear issues on the 2 remaining b/blocks left behind. The friction generated by high rpm's had managed to deteriorate b/blocks physical length to where they could no longer nestle against its accommodating brake ring offering zero friction.
After trial and error, I decided to upgrade the stock spring loaded centrifugal system and it's inferior b/blocks by fitting blocks from other manufacturers' reels with great success. These blocks operate as a constant, rather than spring loaded and no further wear problems are noted in many years use.
Round profiled b/blocks are needed to accommodate round pins. I pluck them from older generation Shimano's like first gen' Trinidad 12/14, Torium 14 and Calcutta 400s, to name a few. All blocks are flanged and grey in appearance.
I also use, and favour, Abu's b/blocks found in older modelled reels with 2 pin centrifugal clutch plates. They are brown in colour.