nothing wrong with blockgaurds. the peopel that say they dotn work are huge supporters of sleeving a block and think its the onyl way to go. If u look at a golden eagle sleeve compared to one of there block gaurds for example, you would think a sleeved block would over heat first. Now, if the gaurd for some odd reason happens to sink to the bottom of the sleeve, you may have some problems. But, if it is done properly, block gaurds can be a big help. Or, you can use a block filler. Some say this method is very ghetto, but, ti works. what you do is fill the block with devcon liquid aluminum