Engine swap

[Korolyov]

I'm looking at bowrider with a 4.3l Mercruiser I/O. Engine block was cracked and the previous owner attempted to fix it. Anyway the only part I'm getting is the water jacket. Can a 4.3l vortec be substituted, are the heads the same?

[rasorinc]

I believe they are the same=both made by GMC. However different years could make the heads different. Contact these people they should know.
http://www.michiganmotorz.com/