the hyd cam lobe has sideways slant to it so it rotates the lifter so they don't wear out, you can use solid but they do not seat flat on lobe
all parts are sold as is, all parts are considered used no warranties or returns paypal/check/money order, shipping is from zip 02891, buyer pays paypal fees 24% IRS 1099A plus 3% of part price, check/money order preferred site is not monitored 24/7 there might be a delay in response