Timing 43 L 2 barrel 1998 Vortec

"I am trying to sort out the t

"I am trying to sort out the timing on the above engine. It has Thunderbolt ignition, and does not have EFI.
In reading both the Merc and SELOC Manuals, they seem to indicate that the motor has to be timed with a scanner,(and a timing light) although they also indicate that in this scenario, the engine should have EFI, and Thunderbolt V ignition..
There is a single line on the damper and a
"v" in the timing chain cover. The timing is spec'd at 10 degrees bttc, but I'm assuming that the lines will give tdc, and not -10.
If anyone has any experience with this engine, and or the scanner needed, I'd appreciate any help that you can give me.
I tried to find the Merc. engine # that should be stamped on the starboard side of the block, just below the cylinder head, and there appears to be nothing there. I'm wondering if the previous owner had a replacement automotive engine dropped in? I've only had the boat for 1 season, and it came in fabulour shape. I assumed that everything was original equipment.
Any help is much appreciated.

Bob."

"the engine could be a replace

"the engine could be a replacement marine engine, but should have a tag on it somewhere, unless it was rebuilt at an engine shop or something. Look in front of the starboard cyl head, there's a pad there hopefully has some numbers on it, unless the block was milled.(not very common)"

"Brian.
I've looked high

"Brian.
I've looked high and low for that tag, or raised letters on the block, and they are not there. The only other place that they put them is right above the starter, but that area is so tight, that I'd need to pull at least the exhaust manifold to find it."