Anybody can make a horrific mistake, once.

Maybe it's because they don't think there are enough gas fumes inside the cover to blow up the boat. 

Thanks John,,that makes sense. But not all inboards....Wonder why cowled outboards don't have them ?  
 

Mark,
You referred to one of your pieces as an air filter or screen. It is actually called a flame arrestor. All inboard motors with carburetors are equipped with flame arrestors.

Well kind of..That's a campfire story. I'll get down maybe this coming week. I'm getting ready to build a crate to ship the Aerojet Cradle and such to Florida. Here if you would like to see the inner workings. Kick up the Quality to 1080 once you get to Youtube.

Hey Mark, did you get to spend some time on the big block problem yet.

The injection system mounts instead of the carb/carbs or supercharger on the intake/exhaust manifold or I suppose that there might have been a set of headers on the exhaust right at the cylinder head
I would say that the injection system was used on the Crosleys that were used in the 3/4 migets
pictures enclosed

Yeah and a leakdown.  I'll pressurize the cooling system. Should be able to see any leaks. I'll shoot the heads too if I find nothing.

While your at it you might consider a compression test too.

Yeah if aviation teaches ya anything. Don't sling parts. Not at $80,000 a component. Verify. Even if you suspect a part,,keep troubleshooting right until the part arrives. I'm not getting any fluid migration. I'm going to flex borescope each cylinder on Friday. It's tough enacting proper troubleshooting on road trips. You always forget to bring something. You know the best thing with the Mustangs,,,the exhaust pretty much has stayed the same over the yrs. I can detect a Mustang coming a mile away. My only GM was a 69 Camaro in Bitburg. I rebuilt the engine with all JC Whitney parts. Thank goodness for APO addresses . I dropped I think 3:08 gears in it for the Autobahn .