Has anyone ran across setups using marine blocks these days? I came across a Camaro that I am interested in, with a 502, and the owner sent me details on the engine and it said "marine block".

Just curious... any and all advice, thanks!

They are good blocks but they don't have any provision for a mechanical fuel pump.

Uhmmmm - the late Mark IV 502's do

The main difference between a 'Marine' and a standard BBC are that the HP/Marine blocks all have Cam Thrust Plate holes drilled and tapped, almost all have 4-bolt mains and most of them have a fly-cut relief at the top of the cylinder to allow additional unshrouding for the intake valve.
(some low performance 'marine' application blocks, mainly 454's, don't have all of these mods)
They also have the Oil Cooler ports drilled and tapped above the oil filter area.

If you can furnish the casting number and date, the Suffix code and any other numbers you find we can most likely decode it's origin

And - they make a fine starting point for most HP builds

I agree !!!

This particular car I am looking at does have an electric fuel pump...

Common on marine applications, as are belt driven fuel pumps on some mercruiser units ...

So is this something you would prefer to have/not to have? Does it really matter?

Using a properly sized and installed electric fuel pump is nothing I would think twice about.
I have owned vehicles with electric pumps since the late 60's

You might want to do a few searches on this site for information on sizing, pressures, installation and elecrical supply system to bring yourself up-2-speed on them.

The only thing I don't like is the absence of the mech fuel pump boss is a dead give-away if you're trying to make it look original.

If its a mark VI the oil pan and timming cover are different that the early model blocks. I had a 555 built on a MarkVI block till a rod let loose. I have a extra pan and belt drive for one now since it wouldnt work on my new dart block. It was a great motor!

Here are the specs that he had provided me for the whole motor:

Marine block
Speed pistons 11.25:1 compression - 0.60 over
Speed Pro rods
10.10 Crank - steel
110 cc heads - cast w/ 233 int. 188 ex valves
Comp Cam roller 578 lift 332 duration
Crane roller lifters
Full roller rockers - Crane
Double roller chain timing gears
Engine balance
New flywheel
Electric vacuum pump
950 Proform Carb w/ mech. downleg
Zoom comp clutch
Drag race driveshaft with solid Ujoints

Does the compression seem to be on the high side at 11.25:1?

Talk to the owners wife (he was out) and she said it can be run on premium gas... but he will mix it with some higher octane fuel on occasion as well. What do you think with the higher compression?

Ugh... not sure I want to have to mess with race gas. This might be a little more "race" engine that Im looking for.

Look at the cam duration - 332 !

This is definitely a race engine. And the cast iron heads make it more prone to detonation.

Ok, like I stated before, kinda new to these engines. How is the best way to get the compression on this car down to 10-10.5:1 and run safely on pump gas???

Would a head/cam swap suffice? Recommendations???

Static compression has very little bearing on whether or not it will run on pump gas. Dynamic compression will decide that and you get that from cam sizing which will set when the valves are fully closed so compression actually starts. With a big enough cam you can run 87 octane in an 11:1 engine.

With that lift, I'm going to assume the 332 is a typo if it's a roller. The biggest solid roller Comp makes is a 322 and it's got over 0.700 lift.