I need advice from a boat mechanic. My cylinder heads have cracked (second time in a year) and the shop doing the work is quoting 20 hours "according to the Mercury Manual" to do the work-at $75 hourly rate. The new Vortec heads for my '99 5.7 EFI Mercrusier are costing $300+ each. The last shop that did the first R & R charged 10 hours. Of course, this is the same shop that installed the new impeller wrong and caused the second incident. So I'm wondering what a good average would be to be charged for the R & R of the cylinder heads. Thanks, Kopy Kat 