Just keep ;ooking around on here. Really bad ass single engines pop up all the time for pennies on the dollar.

You are not going to find a 502 at a scrap yard. They are actually a 8.2 and were never installed in any production vehicles.

How much horsepower are you looking to make is the real question. Forget scrap yards. Even if you found a plentiful 454 truck engine, your still gonna get cast cranks, cast rods, and cast pistons, none really ideal for a high power marine engine.

By the time you get a old used block, have it machined, fingers crossed its even useable, buy a complete decent brand stroker crank, rods, pistons, etc, you'll have almost as much in the shortblock as what you can buy one shipped to your door, assembled and ready to go, all brand new parts, and better block.

Also, if starting from scratch, the cost is pretty much the same whether you want a 454 or 598. Do you have the heads already that you want to use? That also plays a major role in block/size choice.

Or, just do like Jeff said, buy a complete engine on here. Lots of good engines for good prices.

The bottom line is HP cost money , how much do you want ? $$$$$$$$$$$

502 is an 8.2 liter, 4.470 bore and same stroke as a 454.
8.1 liter is a 496 with 4.25 bore and a long stroke crank - which is pretty much the 454 stroker you are talking about building...

Definitely better to start with a 502 block and build from there.
The 4.5" bore unshrouds the valves which is good for some free extra hp.

A 540 based on a 502 std deck block is the cheapest way to get a "big motor".

But they didn't put ANY 502's in cars. They are all marine/aftermarket/crate motors. Plenty of em out there, though, but you won't find one in a car boneyard unless it has a lot of boat motors in it.

Thanks for all the information everyone. The reason I would like to start with a bare block is mostly because of budget reasons. It is easier for me to do bits and pieces a little at a time. May take me over a year to build it but I just don't have 10k+ to plunk down on a complete motor at one time. Doing a lot of the work myself I believe I can save some cash and build a good reliable motor. I would like to get a 502 block but it just seems that the 454 blocks are much more plentiful.

The best and cheapest way is to put all that money in a sock piece by peice and forget about it while running your boat the way it is until you get it all out of your system adn sell your boat.

Then go find that money you stashed away and have a great time.

Its hard to find a good used 502 block. With a tall deck 454 you could use a lot bigger crank than a standard deck. Many ways to go with it, 489, 496, 540....... all a matter of time and money.