BBC Pro1 Head Gasket Help/Question?

[A69540]

I purchased a set of Dart BBC 320cc Pro1 heads for a 540 I'm building. My block is World Products Merlin II cast iron block. The block is supposed to be compatible with all Mark IV parts. The Dart documentation that comes with the heads recommends the use of a FelPro #1017 head gasket on a Mark IV block. The shop where I went to purchase the head gaskets from tell me I want a FelPro #1047 head gasket? When I look up part #1047 it specs that same as a #1017 but it says I need to drill 3 extra holes on a Mark IV block in order to use these gaskets. What am I missing here? Why would I just not use the #1017 like Dart suggests? I found this on another website does it hold true?
MrkIV blocks - use all Mrk IV, GenV or GenVI heads with GenV,VI head gaskets

GenV blocks - use all GenV,VI heads with GenV,VI head gaskets. MrkIV heads (early production factory heads -290, 781,063,049,291) use special adapter gaskets.

GenVI bocks - use all MrkIV or GenV,VI heads with GenV,VI head gaskets.

[rskrause]

Use the 1017-1 or the 1017-2 if you need a thicker gasket (.039 v. .051").

Richard

[Awesome Bill]

I purchased a set of Dart BBC 320cc Pro1 heads for a 540 I'm building. My block is World Products Merlin II cast iron block. The block is supposed to be compatible with all Mark IV parts. The Dart documentation that comes with the heads recommends the use of a FelPro #1017 head gasket on a Mark IV block. The shop where I went to purchase the head gaskets from tell me I want a FelPro #1047 head gasket? When I look up part #1047 it specs that same as a #1017 but it says I need to drill 3 extra holes on a Mark IV block in order to use these gaskets. What am I missing here? Why would I just not use the #1017 like Dart suggests? I found this on another website does it hold true?
MrkIV blocks - use all Mrk IV, GenV or GenVI heads with GenV,VI head gaskets

GenV blocks - use all GenV,VI heads with GenV,VI head gaskets. MrkIV heads (early production factory heads -290, 781,063,049,291) use special adapter gaskets.

GenVI bocks - use all MrkIV or GenV,VI heads with GenV,VI head gaskets.

You should use the 1047, this head covers all blocks and has a very nice water coolant passage sealing option that will work all all applications. The thing I like is that this has Stainless Steel Wire and will not deteriorate like the steel will. That is the main difference. You could drill those extra bolt hole if you wanted something to do, but your not required to do that. That was for the older blocks that GM never drilled and you should do to bring it up to new school better cooling. The new blocks and heads have been upgraded.

The 1047 is basically a better head gasket and used for marine applications. Pre flattened wire will move with Nitrous or turbo stuff. Depends on what your doing. You can't go wrong with the 1047, I would use them.