These are 2020mfg from Power Solutions International. They are 8.8 liters / 535 cubic inches.
They are essentially Gen7 chevy big blocks and share much of the features of the Chevy 8.1/496 that came in trucks and boats... only better.
I swapped in 10:1 forged pistons, 496HO marine camshaft and PAC1219X beehive valvesprings. Its otherwise all original, right down to the rings and bearings.
The factory intake fits a 92mm throttle body... so i then ordered a Holley TerminatorX engine management system. Having never messed with injection before, the learning curve was steep... but after a week of playing with it and several remote desktop connections, I finally have it running and idling. Still need to tweak the idle down... but at least i can hear it run.
Attached File Attached File PSI 8.8, Mercruiser 496HO cam, Holley Terminator X idling at 950
PSI 8.8, Mercruiser 496HO cam, idles with mufflers and no IAC