Lars is correct about being able to buy cam cleats with SWL's up to 500
pounds. At least from Harken. Harken does make a line of off-shore cam-cleats
which are rated for 500#.
I checked my 1999 Harken catalog and they make something called an "off shore
cam-matic" (part #280) and a "double cam-matic" (part #412). The listed
retail price for just the cam (not including a fairlead) is $37 for the #280,
and $56 for the #412. The #328 Fairlead is about $9. Street prices should be
at least 20% lower than the published retail.
However, that's about the same price on a "per line" basis as a Frederikson
triple clutch that I bought for a little over $100
Best,
Judy