I have the 377's [ not the scorpions ] and couldn't be happier with them [87 octane ]. They spin faster and more power than standard BB. Unless you're a midget ,the big blocks are difficult to access even to the spark plugs . Here's a picture of my engine bay , clearly a lot more room between the two engines than with big blocks.
http://www3.telus.net/spectrasonly/twin%20377
Match made in heaven for a 24' boat
http://www3.telus.net/spectrasonly/IMG_1607%20copy.jpg
Have Bravo 1X drives with 1.65 ratios that allows my bravo1 26P's to spin up to 5150 rpm's. Put some 28's for more top speed .Some penalty in the holeshot , but less rpm's for longevity.
http://www3.telus.net/spectrasonly/twin%20bravo%201X
loafing about http://www3.telus.net/spectrasonly/J...166%20copy.jpg