Best way to check engine?

Hopefully this question doesn't come across as too stupid, but here's the deal.

Back in November I paid a guy to winterize my boat (maybe a mistake, but I was going out of town and wanted it done before it froze)

I've been thinking about replacing the drain plugs with petcock valves, so earlier tonight I pulled the plugs so I could make sure I got valves that fit. The exhaust manifolds were dry, but the drain plugs on the block poured out water :( Turns out the guy didn't pull the plugs on the block.

I'm in TX so I might be ok (fingers crossed). We plan on taking it out this wknd and firing it up. Assuming it starts and runs fine, is that enough? Or is there a more exhaustive check I should do to ensure there was no damge to the block?

Run the engine. Check for leaks. Also check the oil to see if there is any water in it.My sister lives near Dallas. She said they haven't had any long lasting cold days.

Sorry to bud in here, but wondering if somebody could tell me where the freeze plugs are on my 1997 GT-40 (Ford block)? Thanks

    If the temp didnt get real cold, youre prob ok because the block being under the engine cover, surrounded by fiberglass, has enough thermal mass that it would have to get below freezing for a while.

    As far as petcock valves go in my opinion, they can be a liability because it shrinks the hole size and can get blocked off by a piece of rust. I had it happen with the petcocks on the 74 M17, where the water just stopped coming out. Put a wire in it and got another gallon. I always like to watch the water come out until stops. Its worth the 5 minutes to put BRASS plugs in.
   My .02                      Jeff....

    SkiDim should have them all. They are OEM on the new PCM engine I bought. The reason for brass is because it is softer than steel, seals better without the need to go as tight, and it will keep from opening up the tapered threads in the block, manifolds, waterpump etc. Its cheaper to buy a few plugs over the years as they wear then to try to fix the threads on the other end. Brass also wont seize up (rust) on you either to allow easy removal.
                               Jeff...

Update...took the boat out yesterday. No visible signs of freezing on the freeze plugs. It fired right up, with no signs of leaks or water in the oil. Checked it out as well as we could. We'll keep an eye on it, but looks like I might have gotten lucky. Thanx for all the info and advice.

I ran it on the water. We were out for about an hour. Like you said, it should have shown up pretty quickly if there was a problem. No leaks and oil looked fine. I'll be taking it out again tonight so I'll be on the lookout again, but I feel alot better than I did a week ago :)