Mercruiser block swap. Timing?

[kbartruff]

Hi,
My father and I are working on our 1990ish 19ft Bayliner. It has the 4.3L engine but the previous owner cracked the block and replaced the block but kept all of the other parts. The new block has the newer timing system but our engine has the old one. The manual for the newer vortec engine says to set the timing at 10degrees but the old manual says set to 8degrees. Which should we use? We have tried both and they work but I wasnt sure if anyone knew if there is a better one. The new block has no information on it and therefore we dont know year.
Thanks,
Matt

 

[Don S]

Re: Mercruiser block swap. Timing?

Assuming when you say timing system that you are referring to the newer cast in composite timing cover, as compared to the older steel one with timing degree marks in it.
If so, go with the 10? BTDC